Link Value Factors - Intro

It's a known fact that no two links are equally the same, in this research I attempted to see every two links as equals. While this obviously makes it impossible to create a 100% accurate piece of content, this - together with the dozens of interesting comments- results in a document that might be of value for everybody who's somehow envolved in building links. The grain of salt that comes with this research is far being outweighed by the value of the present data.

While some might use this document for entertaining purposes only, these results and factors can be enterpreted by everybody as an indication that, while lots and lots of different factors come into play of the process, building links sure isn't rocket science.
It's way cooler.

Wiep Knol

Link Value Factors Explained

In the style of SEOmoz' Search Engine Ranking Factors, this page includes the opinions of 17 well respected, international SEO and Link Building professionals on nearly 40 factors that possibly influence the value of a link. My opinion about each factor has been included into every score as well. Although not every possible influencing factor, nor every possible opinion has been included, this page covers the majority of the factors and is pretty accurate. At least, in my opinion.

The idea behind this research was to determine which factors professionals from the field of SEO consider to be of influence on the value of a link and/ or on the potential amount of link juice that a link can pass. Because most of us understand the value of links in terms of traffic, this research mainly focuses on the value that search engines may allocate to a link.

Every factor has been rated on a scale from 1 to 5 by the participants:

  1. Not of any influence on the value
  2. Fractional effect on link value
  3. Moterate influence on the link value
  4. Strong influence on the link
  5. Very strong influencing factor

Section 4 of this document contains seven possible dampening factors. Here, dampening doesn’t necessarily mean that these factors have a negative effect (e.g. as in a penalizing effect) on the link in question, but it only means these factors might be able to make the link of lesser value. These factors could have als be named "possible link juice reducing factors", but dampening factors was shorter. Every dampening factor will be highlighted with (DF) in the Top 10 below.

These factors have also been rated on a 1 to 5 scale:

  1. No negative effects at all
  2. Slight negative effect on the value
  3. Somewhat negative effects
  4. Big negative effect on the link value
  5. Maximum negative effect


Like stated before in the intro, no two links are equally the same. Also, no two search engines are equally the same. This is why all results below are relative, but nonetheless pretty interesting as well.

This page is also available as a full color pdf or printer friendly pdf.

Participants

Patrick Altoft
BlogStorm

Martijn Anschütz
M4M Zoekmachine Marketing

Hamlet Batista
Hamlet Batista dot Com

Jim Boykin
We Build Pages SEO Company

Bob Gladstein
Raise My Rank SEO Services

Peter van der Graaf
Peter van der Graaf

Wiep Knol
Wiep.net

Michael Martinez
SEO Theory

Debra Mastaler
Link building campaigns and link training

Maurizio Petrone
Esperto SEO

Arturo Ronchi
3D Live Statistics

André Scholten
André Scholten

Ralph Tegtmeier
Cloaking aka IP Delivery for optimal SEO

Barry Schwartz
Search Engine Roundtable

Joost de Valk
SEO & Blogging

Peter da Vanzo
Link Juicy

Aaron Wall
SEO Tools

Eric Ward
EricWard.com - Link Building Strategies

 

Link Factors

The first 9 questions will focus on the link factors. This means only factors directly related to the link itself and no on-page or on-domain stuff yet.

01. Anchor Text
Is the anchor text of a link of influence on the value of a link?
For example, does it matter if the link is a URL, the company name or a relevant keyword?
Bob Gladstein: “Even with Googlebombs ostensibly shut down, there's no question that anchor text makes a big difference.”
Jim Boykin: “I believe that so are the words near your link.”
Eric Ward: “Multiple factors play into the ultimate effect of anchor text. The best anchor text in the world is meaningless if the site has not shown previous signals of trust.”
Aaron Wall: “You can see how powerful this just by testing adding a new related word or two in your inbound anchor text and see how quickly you start ranking for phrases including that word.”
Joost de Valk: “In my experience, even good anchor text on otherwise bad links might increase your rankings.”
Peter van der Graaf: “As long as it doesn't look spammy, having perfect anchor text is easy SEO”
Patrick Altoft: “Anchor text has no bearing on the trust that a link passes but it has a big effect on rankings for similar terms.”
André Scholten: “The most important aspect of a link is the anchor text. It (should) tell everything about the page that is behind it.”
Peter da Vanzo: “Depends on which search engine you're talking about as to the degree of influence.”
Maurizio Petrone: “You should differentiate... having all or most of your backlinks having the same anchor text is not a good idea. And the distribution is taken into account when it's time to assign value to each single link.”
Ralph Tegtmeier: “It's a volume thing, though not linear. Even tons of non-anchored links may give you some linkjuice but only minimally so.”
Hamlet Batista: “Keyword rich anchor text still remains a very important factor, but links with URLs or brand names are important to have too.”
4.6
High influence
on the link value
high agreement
 
02. Age of the link
Does the age of a link have an effect on the value of a link?
For example, is there a difference in value if a link is two weeks or two years old?
Debra Mastaler: “More than the link, if the page the link sits on has age, that's more helpful.”
Bob Gladstein: “The ages of the site and the page clearly matter, so it would make sense that the age of the link would make a difference, but I haven't tested this.”
Joost de Valk: “Old backlinks from old sites will really do you well :)”
Peter van der Graaf: “A link ages within 3 or 4 months. After that the value increase is neglectable.”
Jim Boykin: “I believe new links give a big push, then the value fades out some, then over time it's worth more again.”
André Scholten: “A long lasting link is a good one if the page it's on still grows popularity also. If not: a good chance the link is devaluating over time.”
Ralph Tegtmeier: “If there's any influence, we haven't been able to detect it.”
3.6
Moderate influence
on the link value
mildly controversial
 
03. Type of link (image, text)
Does the type of link, for example a text link or an image link, have an effect on the value of a link?
Bob Gladstein: “In my experience, a text link carries more weight for its anchor text than the alt attribute of an image link. However, you have a little more freedom in using images in a menu, since what would be a text link with an anchor of "Home" can alternatively be an image link with an alt attribute of "Home - Rare and Used Books".”
Ralph Tegtmeier: “Cannot discern any particular value in non-text links.”
Jim Boykin: “An image with focused alt text is near equal to link text I believe.”
Hamlet Batista: “The alt text of an image when placed inside a link carries the same or similar weight to the link text alone”
Aaron Wall: “If it is an image you need to remember alt text.”
André Scholten: “Images can have a title and alt attribute, but this kind of text is not as strong a with a normal anchor text.”
Peter van der Graaf: “Alt tags are of less value than normal text”
Patrick Altoft: “As long as the images have alt text there isn't a huge difference.”
Eric Ward: “Again, multiple factors play into the ultimate effect of text and/or image links. The best image links in the world are meaningless if the site where they reside has not shown previous signals of trust.”
Maurizio Petrone: “If the link is an image, the value of ALT attribute counts as an anchor text. Also, banner-like proportions (as 468*80 and so on) should be avoided, and larger images are likely to be taken in a greater consideration than smaller ones.”
3.5
Moderate influence
on the link value
highly controversial
 
04. Surrounding text (near-link relevance)
Does the content of a text that directly surrounds a link of positive influence the value of a link?
This question only covers the content that surrounds the link directly. The overall page relevance will be mentioned later on.
Eric Ward: “Multiple factors play into the ultimate effect of surrounding text. In some cases it will be useful, in some cases it will be useless.”
Bob Gladstein: “It's not clear to me whether it's more a matter of the general theme of the page or just text in the area of the link, but it does make a difference.”
Peter van der Graaf: “Surrounding text in de direct vicinity of a link is important, but links in the vicinity are just as important.”
Maurizio Petrone: “Nowadays, anchor text is by far a more important factor rather than the text surrounding the link. If the text is not unique (within the website, too) its value decreases long more.”
André Scholten: “Context can mean a lot, there a words that have a total different meaning when placed in a different context. Search engines will determine which linked page is more relevant when searched for a specific context.”
Hamlet Batista: “This is documented in the original paper describing Google's search engine and on one of the latest patents. Extensive testing is required to be certain.”
Ralph Tegtmeier: “More of an informed guess than a scientifically proven assertion. I'm fairly confident, however, that proximity of keywords and targeted search terms will play a fairly important role soon.”
3.3
Moderate influence
on the link value
mildly controversial
 
05. Number of links
Does the amount of links, for example a single link or a site wide link, have an effect on the value of a link?
Ralph Tegmeier: “There seems to be some indication that links are being treated as potential singularities by the search engines. I.e. if site A points hundreds or thousands of links to site B, the individual links' value may be demoted. That's why we wouldn't recommend going for site wide links though some exceptions apply, e.g. blogrolls.”
Aaron Wall: “Sitewide would of course pass more PageRank and help you get crawled deeper.”
Joost de Valk: “I don't think sitewides count as much more than two or three links, but your mileage may vary depending on the size of the site.”
Arturo Ronchi: “I never was a fan of the complete hilltop analysis but I do think that multiple links from a single domain are dampened and don't count as much as if they where coming from multiple domains.”
Bob Gladstein: “I've seen run-of-site links be pretty much ignored. When their target was changed to an internal page on the linking site, which then linked out to the target (so there was only one link to the target site), it seemed to make a big difference.”
Peter van der Graaf: “This factor is increasing in value, because it could indicate link buying and other Google spamming factors.”
André Scholten: “Site wide links are good votes for the importancy of your site, single links can be good votes for relevancy reasons.”
Maurizio Petrone: “It definitely depends on the case. Sometimes is better to have a single link back from an internal page, sometimes is better to have a sitewide backlink.”
Eric Ward: “It will depend on quality of the source sites.”
Hamlet Batista: “When you get multiple links from the same domain, search engines put a threshold to the amount of link juice you get”
Debra Mastaler: “More and more, sitewide links are being devalued as the engines proactively look for these patterns and discount the links. Getting one or a few links from a page ranking well is preferable to site wides.”
3.2
Moderate influence
on the link value
mildly controversial
 
06. Location of link on page (boiler plate)
What kind of effect does the location of a link on a page, for example blogroll, body or footer link, have on the value of a link?
This factor only covers the position of the link on the linking page.
Hamlet Batista: “At least MSN has some research documents suggesting they pay attention to this.”
Bob Gladstein: “It depends partly on the page linking out, i.e., if the page contains footer links that are clearly paid advertisements, I would think that the link, if it were placed in that area, would be given less (if any) value.”
Eric Ward: “It will depend on the source site.”
Ralph Tegtmeier: “If there's any influence, we haven't been able to detect it. There is, however, some indication that the effect of footer links may be relatively weak, same goes for repetitive site wide links.”
Maurizio Petrone: “Modern algos are capable to detect repeated portions of pages within a site or within a network, so this has to be taken into account when planning your linking strategy.”
Aaron Wall: “In content in the middle of a sentence is both hard to devalue and hard for them to want to devalue.”
Joost de Valk: “Blogroll and footer links seem to be devaluated a bit, with footer links being the most devaluated..”
André Scholten: “As I said before, a footer link can be on top in the source code, so position doesn't matter.”
Jim Boykin: “I believe a link in the body area of a page, in a sentence, with words on both sides of the link, are way more valuable than footer or sidebar links that are stand alone links.”
Debra Mastaler: “Traditional navigational spots tend to be less authoratative although I've seen the reverse to that as well. Good anchors sitting on pages with higher pagerank scores tend to help ranking, even if they're in footers.”
2.9
Some influence
on the link value
mildly controversial
 
07. Reciprocity
Is it a one way link, or are you linking back?
Patrick Altoft: “Links are not devalued purely because each site links to each other somewhere. As long as the links are not both from links pages they still pass weight.”
Joost de Valk: “Lots of reciprocals will get you a weird profile, some reciprocals won't hurt though.”
André Scholten: “A reciprocal link is not so effective as a one-way link. It has the smell of arranged link schemes.”
Jim Boykin: “I believe in trading only with people who are very related to you, and only on a limited basis.”
Hamlet Batista: “Few reciprocal links are fine, but is far better to focus on the one-way ones.”
Eric Ward: “It will depend on the sites and the subject matter, and the historical subject specific reciprocity tendancies”
Aaron Wall: “If fairly natural and from within community no problem, but if too many links are on a reciprocal links page and most of your links are reciprocal expect mininmal love from Google, especially if your site is new.”
Peter van der Graaf: “The value is reduced by a small factor if the link is reciprocal”
Bob Gladstein: “I don't think reciprocal links are always bad, but they do seem to send a signal that the link is a trade rather than a vote. If you're going to trade links, at least try to point them to internal pages instead of the obvious links page on site A to home page of site B, links page of site B to home page of site A.”
Maurizio Petrone: “Reciprocal links are not "The Evil", but you should avoid them as your main link popularity strategy.”
Ralph Tegtmeier: “(Note - this type of question doesn't relate too well to the rating structure.) While reciprocal links aren't half as effective as they used to be only 2-3 years back, they can still exert some influence.”
2.9
Some influence
on the link value
controversial
 
08. Target page (where the link points to) location
Is the target page (does the link point to your homepage, is it a deeplink, does it point to an orphaned page) of influence on the value of a link?
André Scholten: “When links point to a homepage the subpages get indirect credit for them. When links point directly to the subpages, they are much more valuable.”
Jim Boykin: “Lots of deep links is key.”
Eric Ward: “As with all things, it is not as simple as people want to make it. No two sites are created equal and thus the links between them cannot be categorized equally.”
Ralph Tegtmeier: “While this depends on a slew of factors I cannot outline in detail here, a short and sweet answer would be: Yes, it's important to deeplink as part of your overall link building strategy. This doesn't impact any given individual link's effect, however. It's more a case of keeping the entire, larger picture in mind.”
Bob Gladstein: “It's certainly important to get links to internal pages, but if the question is whether such links carry more weight based solely on the target, I'd have to say no.”
Debra Mastaler: “The goal should be to point to the page that will bring you the greatest ranking/money/positive impact, home and inner pages should do that.”
Peter van der Graaf: “As long as the target page is the same target as every link on that theme, you keep focus on that page. The textual relevance is less important than the contextual relevance.”
Maurizio Petrone: “Again, differentiation is the key. You should have some links pointing to your home page, and some strong deep links too.”
Hamlet Batista: “Deeplinks are usually more natural and reflect editorial vote, but home page links are not bad at all. The goal must be to have a natural looking link profile”
Aaron Wall: “You need to target the anchor text to the right pages so you have the right pages ranking for relevant queries. Also if too many links point to just one page that might not seem as natural as if you have many deep links.”
2.9
Some influence
on the link value
controversial
 
09. Location of link in source code
Does the location of the link in the source code (for example top 5% or last 20 Kb) have an effect on the value of a link?
This factor only covers the position of the link in the page's source code.
Peter van der Graaf: “Smarter search engines like Google recognize block layouts on a page. This is based on code!”
Ralph Tegtmeier: “If there's any influence, we haven't been able to detect it. However, this may be different for very large pages, which is explained by looking at the crawling process. E.g. if the search engine spider is set to cap crawling beyond 300kb page weight (again: this is merely an example, not a set value), it stands to reason that links located outside that range will not be spidered either.”
Hamlet Batista: “It is a good idea to place the link high on the page. If you place it at the bottom and the page is to big (>100k), your link might not get indexed.”
Bob Gladstein: “Not unless the page is so big that it doesn't get completely spidered.”
André Scholten: “With a good separation of structure and layout (HTML vs CSS) a link can be anywhere in the code while it can be also anywhere on screen. So it doesn't matter where it's placed.”
Jim Boykin: “I believe where on the page is much more important than where in the source code a link is located.”
Eric Ward: “It will depend on the source site.”
Maurizio Petrone: “In the past, search engines spiders had a limit on the size of the document they downloaded, so having your link in the first portion of the linking page's markup or in the very bottom could make the difference between having your link counted or not. Nowadays spiders doesn't have such limitations, but prominence has still some importance.”
Debra Mastaler: “Above the fold gets more eye time, greater chance to be clicked. This is usually where topical content sits, good to be there and not the 101st link toward bottom.”
1.9
Low influence
on the link value
mildly controversial
 

On Page Factors

This set of 14 factors discusses on-page factors that might (or might not) influence the value of a link. In stead of factors that are part of the link or are in the link's direct surroundings, the focus is on the pages that lists the link here.

01. Page authority (in inbound links)
Does the page have a lot of incoming links from external pages?
Does it have an effect on the link's value if the linking page has a lot of backlinks?
Arturo Ronchi: “If a link carries more weight when it resides on a page which has 10k links pointing to it ? Oh yes, the more the merrier.”
Bob Gladstein: “The more authority the linking page has, the more authority it gives out when it links. However, just having a lot of links doesn't necessarily make it an authoritative page. It will depend on where those links are coming from.”
Ralph Tegtmeier: “This is about trust (not to be confused with Yahoo!'s TrustRank algorithm) and authority (the "hub" concept), etc.”
Jim Boykin: “I strongly believe that if you get a link from someones page that has a lot of people linking to it, that it carries much more value that getting a link from someones page that no one else links to. Get links from pages that have backlinks from other people (I also believe that homepages are an exception (I believe they are treated differently)).”
Debra Mastaler: “Depends on the quality of what's linking in.”
Aaron Wall: “See Jim Boykin's great post on this one”
André Scholten: “The more popular a page, the more popularity he can pass on.”
Hamlet Batista: “Links from highly linked pages are usually better.”
Eric Ward: “It will depend on the source site.”
4.4
High influence
on the link value
mildly controversial
 
02. Amount of outbound links on page
Does the amount of outbound links on the linking page have an effect on the value of the link?
(outbound links only)
Hamlet Batista: “As per the PageRank formula, the more outbound links the less link juice is passed.”
Jim Boykin: “I love getting links on pages that have lots of backlinks to them.”
Ralph Tegtmeier: “In terms of PageRank, this is a no-brainer, of course. The less outgoing links, the stronger their impact.”
Peter van der Graaf: “Amount of links is important. Internal/external ratio isn't.”
André Scholten: “The less outbound links a page has the more popularity the remaining outbound links get. Less is more.”
4.3
High influence
on the link value
mildly controversial
 
03. Total amount of links on page
Does the total amount of links on the linking page have an effect on the value of the link?
(both inbound and outbound links)
Debra Mastaler: “Google reps have been quoted as saying spiders stop spidering after going through 100 links on a page.”
Bob Gladstein: “Absolutely. The more links in, the more juice the page has to distribute. The more links out, the less juice each linked-to page receives.”
André Scholten: “The less outbound links a page has the more popularity the remaining links get. The more inbound links the page has the more popularity he can pass through.”
Eric Ward: “Sometimes yes, sometimes no. It will depend on the source site's previosuly earned trust.”
Peter van der Graaf: “I've done thousands of tests that confirm this importance.”
Ralph Tegtmeier: “Another common myth dating back to the mid 90s that doesn't seem to hold water anymore.”
4.1
High influence
on the link value
mildly controversial
 
04. Page authority (in internal links)
Does the page have a lot of incoming links from other pages on the same domain?
For example, does it have an effect on the link's value if the page is well linked or if the linking page is an (almost) orphaned page?
Jim Boykin: “Yes, I believe that the importance of a backlink is based on that page's internal and external link worth. If you get a backlink from a page of a site that has 1000 pages, and that specific page only has 10 internal backlinks it's not worth as much as getting a link from a page that has an internal sitewide link (1000 internal backlinks).”
Hamlet Batista: “Internal links to the page carry weight but not as much as external ones.”
Arturo Ronchi: “I give this a 5, merely because I think that if a page has more value (or PageRank for lack of a better word) it has more strength/value to pass with the link.”
André Scholten: “The more popular a page, the more popularity he can pass on. But often this is not as strong as a page with a lot of external inbound links.”
Ralph Tegtmeier: “Decidedly yes!”
Aaron Wall: “A well integrated page passes a stronger vote.”
Eric Ward: “I've ranked pages #1 with nothing more than a single link from a single page.”
3.8
Moderate influence
on the link value
somewhat controversial
 
05. Relevance of other outbound links
Does the relevance of the other outbound links on the linking page have an effect on the value of the link? For example, is your link between a link to a car dealer and a link to the paleontologist society?
(relevance of the outbound links only)
André Scholten: “The more ontopic links vs offtopic links the better it is. It's a good signal if all links point to matching subject pages.”
Debra Mastaler: “Yes, they're probably discounted, especially if they're in footer locations.”
Hamlet Batista: “No evidence that this is being measured”
Ralph Tegtmeier: “This is a pervasive myth we don't subscribe to. Possibly, search engines will indeed be able and willing to implement Latentent Semantic Indexing (LSI) as a major ranking factor in the near future but presently we don't see any tangible indication that they're doing it already.”
Jim Boykin: “Not only relevance, but trust.”
Bob Gladstein: “The subject-matter of the pages being linked to is likely to affect the anchor text of those links, which in turn will affect the relevance of the page itself to that text. Therefore, if all the links on the page are pointing to car dealerships, the linking page is more relevant to car dealerships, and that should increase the weight of the links.”
3.4
Moderate influence
on the link value
somewhat controversial
 
06. Age of the page
Is the age of the page of influence on the value of a link?
For example, is a new link on an older page of more value than a new link on a new page?
Eric Ward: “Sometimes yes, sometimes no. You have to know what to look for. It will depend on the source site's previosuly earned trust.”
André Scholten: “A link on an aged page is a good one if the page it's on still grows popularity also. If not: a good chance the link is devaluating over time.”
Ralph Tegtmeier: “At this point in time it's still unclear to us whether the age factor pertains to the domain as such or a page in particular. It may well be both but this is something I would be at a loss to back up with serious statistical data.”
3.4
Moderate influence
on the link value
mildly controversial
 
07. Page relevance (contextual relevance)
Is the page overall contextually relevant to the subject of the page where the link is pointing to?
For example, this would mean a link on a car dealer website to a car manufacturer.
Aaron Wall: “Becomes relevant if you have many off topic links and get hand reviewed. Also getting links from on topic expert pages helps during local reranking.”
André Scholten: “Relevancy is king, if a page is about the same subject as the linked paged the link is a highly valuable link.”
Eric Ward: “It will depend on the both source and destination site.”
Arturo Ronchi: “I think especially Google is working in this field to make the pass-link-juice-algo more "intelligent". But quantity still works. Don't know for how long though.”
Maurizio Petrone: “This is definitely the direction torwards which engines are going, but isn't still a really strong factor.”
Joost de Valk: “Links from high profile sites will help no matter if they're contextually relevant or not, but it sure does help if they are relevant!”
Ralph Tegtmeier: “This is a pervasive myth we don't subscribe to. Possibly, search engines will indeed be able and willing to implement Latentent Semantic Indexing (LSI) as a major ranking factor in the near future but presently we don't see any tangible indication that they're doing it already.”
Hamlet Batista: “Maybe only Ask.com considers this.”
3.2
Moderate influence
on the link value
somewhat controversial
 
08. Quality of other outbound links
Does the quality of other outbound links have an effect on the value of a link?
For example, is your link between a link to CNN.com and a link to Adobe.com?
(quality of the outbound links only)
Ralph Tegtmeier: “This seems to involve a bit of convoluted reasoning which, in a nutshell, goes like this: If a page links to authority sites like CNN and Adobe, it's overall standing in terms of "trust" or "authority" seems to improve, provided other factors are a given (e.g. a decent number of strong inlinks). This itself will obviously impact that specific page's outlinks' value.”
Hamlet Batista: “This affects the linking page and affects the value of any link indirectly.”
Debra Mastaler: “If your link sits between CNN and Adobe then no, you'll probably not be bothered either way.”
André Scholten: “When your site is positioned between some greater ones it can be a signal your site is important also.”
Arturo Ronchi: “I don't think that a one way link to an authority website alone can place your page/domain/node in their neighborhood.”
Jim Boykin: “Co-citation is a wonderful thing.”
3.1
Moderate influence
on the link value
somewhat controversial
 
09. Amount of non-linking content on page (is it a link or content page)
Is the amount of linking versus the amount of non linking content of influence on the value of a link? For example, the percentage of linking content on a sitemap or in a directory is much higher than in a descriptive or an informational page. Does this have an effect on the value of the link?
Maurizio Petrone: “Descriptive, informational pages are likely to pass more information about the target page, but the link "pure" strength is not said to be different between cases.”
Arturo Ronchi: “Besides the fact that the link value is divided among the number of links on a page, I do think that a link from a nice editorial page has more value than a link from a directory.”
Aaron Wall: “If a page has many links then each link gets less equity. The pie is split into many pieces.”
Ralph Tegtmeier: “We're on fairly slippery ground here. As with so many factors viewed in isolation, in real life they're actually intertwined and co-dependent on various others. E.g. there are reports by link spammers about getting good results from massive pure link lists sans content (apart from anchor text). Then again this obviously begs the question how to actually define "value" and "effect" or "results". If it's merely about getting a page spidered and indexed, different standards will apply compared to getting pages ranked well.”
Hamlet Batista: “You don't want your link on pages that are only a bunch of links with no descriptions”
Eric Ward: “It will depend on the source site's previosuly earned trust.”
Bob Gladstein: “Obviously, the sheer number of links on the page makes a big difference. Whether the ratio of anchors to normal text makes a difference I don't know.”
André Scholten: “The less links a page has the more popularity the remaining links get. Less is more ;)”
2.9
Some influence
on the link value
mildly controversial
 
10. URL of the page
Is the URL structure of the linking page’s URL (clean url, url with keywords, parametered url) a possible influencing factor on the value of a link?
Jim Boykin: “I believe it works a tiny bit to a point...unless you over do it.”
André Scholten: “Not relevant at all (in most cases). Searchengines can handle url's with parameters just as good as clean url's. But in some cases sites with parameters in the url's have duplicate content issues because the use of a different order of parameters. In those cases their pagerank is spread amongst different url's. And that lowers the value of the links on their pages.”
Aaron Wall: “Needs to be good enough to get indexed, but doubtful that it has much weight beyond that.”
Maurizio Petrone: “Has (bad) influence only if the URL structure affects the spidering process of the page (i.e. SessionIDs in URLs and so on)”
Hamlet Batista: “You don't want your link on a dynamic page with too many parameters.”
Ralph Tegtmeier: “Overall, "parametered URLs " still seem to be considerably inferior to clean URLs or those encompassing keywords.”
Arturo Ronchi: “I give this a 2 because keywords in the URL can give a contextual relevance. A clean URL or parametered URL doesn't give any influence.”
Eric Ward: “Sometimes yes, sometimes no. You have to know what to look for.”
2.6
Some influence
on the link value
controversial
 
11. Page relevance (words only)
Is the content on the page wordly relevant to the subject of the page where the link is pointing to?
For example, a page about an Orange (the fruit) links to a page about Orange (the color) and Orange (the brand).
Jim Boykin: “This works for me ;) ...but also one should note the related pages and the types of sites that link to the page you're getting a link from.”
Joost de Valk: “I'm afraid search engines won't be very good at recognizing this :)”
Maurizio Petrone: “I'm waiting for the moment when "word-influence" will be near-zero.”
Ralph Tegtmeier: “This is a pervasive myth we don't subscribe to. Possibly, search engines will indeed be able and willing to implement Latentent Semantic Indexing (LSI) as a major ranking factor in the near future but presently we don't see any tangible indication that they're doing it already.”
Arturo Ronchi: “I think especially Google is working in this field to make the pass-link-juice-algo more "intelligent". But quantity still works. Don't know for how long though.”
Hamlet Batista: “Current search engines cannot tell the difference.”
André Scholten: “Google can separate the different Oranges, but it's not that good on all subjects. So sometimes it can be a nice contextual link if only words match.”
2.6
Some influence
on the link value
high agreement
 
12. Page authority (in PageRank)
Does the Google Toolbar PageRank have an effect on the value of a link?
As it is impossible to determine the actual PageRank, this question covers Toolbar PR only.
Eric Ward: “It will depend on the source site.”
Ralph Tegtmeier: “As we see it, TBPR is merely a toy without significant value of its own. As Google has repeatedly pointed out, it's for "entertainment". Whether TBPR reflects internal, non-publicized PR at all is really anybody's guess. This said, PR in general may indeed have a moderate effect on a given link's value though less so in terms of pushing a linked page's ranking rather than keeping it out of the Supplemental Results index as well as getting it spidered and indexed in the first place.”
André Scholten: “The TBPR is a nice indicator of the popularity of the page the link is on, but it's not a huge factor.”
Patrick Altoft: “You can't see if for the first 6 months anyway.”
Debra Mastaler: “If you're paying for links, then yes, the higher the measure of green the more expensive the link will be. From a ranking perspective, higher TBPR means there are a large number of quality links pointing to a page so a link sitting on that page could be considered more valuable especially if it didn't use NF.”
Jim Boykin: “Fractional... things to note: many new pages have value yet haven't been assigned PR yet... and many high PR sites that have a history of selling links have no value.”
Hamlet Batista: “The fact that Google keeps playing with the green bar is making the toolbar less and less useful.”
Arturo Ronchi: “Assuming that TBPR is a reflection of the real PR. Again a link on a PR 7 page has more value than a link on a PR 3 page.”
Bob Gladstein: “It's worth looking at, but only insofar as it may point out a problem. That is, I don't care whether the page is a 4 or a 5, but if it's a grey bar that's going to give me reason to explore possible reasons for it, like whether internal links to the page are nofollowed.”
Joost de Valk: “Toolbar PR is not used in any algorithms IMHO, internal PR is, but you can't look at that.”
Maurizio Petrone: “Really, no more. It's one of the last things I take into account when considerating candidate pages in my link building campaingns.”
2.4
Some influence
on the link value
controversial
 
13. Last date of page edit (content freshness)
Does the update frequency of a page have influence on the value of a link? Is a link on a page that is being updated frequently of more value than a link on a page that has been edited only once (while inserting the link)?
Joost de Valk: “Depends on how you define this... The only value a search engine can trust here is when it was last changed according to it's own spider data. HTTP headers have nothing to do with that :)”
Ralph Tegtmeier: “Pages that are updated frequently will typically be spidered in shorter cycles, too. This by itself seems to exert a strong influence. Arguably, such an effect may be offset by other factors. E.g. a static page that's hardly ever modified may still point strong links to a site if said page has a strong trust and authority standing by itself.”
Hamlet Batista: “It depends on the type of query.”
Eric Ward: “Not always. You have to know what to look for.”
Jim Boykin: “If anything, I'd believe that getting a link on a page that doesn't change much would be worth more than a link on a page that changes all the time.”
André Scholten: “Old links can be as valuable as frequently updated ones. There are too many other factors to answer this question correct.”
Bob Gladstein: “I've never seen strong evidence that page freshness affects anything other than how often the page is crawled.”
2.4
Some influence
on the link value
somewhat controversial
 
14. Page type (.html, .php, .pdf, .doc)
Can the extention of the page that links to you, for example .php, .pdf, .html or .aspx, influence the value of a link?
Jim Boykin: “I like pdf's every now and then.”
Peter van der Graaf: “PDF and doc excluded because they are different filetypes, there is no difference.”
Arturo Ronchi: “Some speculated that a link from a PDF would have a more permanent nature and would therefore carry more weight. But I can't confirm this. One would see more PDF spamming if it where true :)”
Ralph Tegtmeier: “No indication that it does as long as we're talking pages that can be rendered correctly via the standard web browsers.”
Peter da Vanzo: “If a document can't be crawled, then the link has click value only.”
Maurizio Petrone: “Evidences confirms that links in PDF files are counted someway differently than links in html pages. If the content-mime-type is HTML, the extension doesn't matter.”
André Scholten: “Most search engines don't handle all formats equally well. Links in .pdf and .doc document's are less valuable than normal HTML links.”
Eric Ward: “Sometimes yes, sometimes no. It will depend on the source site's previosuly earned trust.”
Aaron Wall: “PDFs may count more than common page types because they take more effort to make and are usually of a higher editorial standard.”
1.7
Low influence
on the link value
mildly controversial
 

On Domain Factors

The following nine factors discuss the on-domain factors. While lots of factors that influence the value of a link are in the direct surrounding of this link, there are several domain wide factors that might influence this value as well. The most important ones will be discussed in this section.

01. Domain authority (in quality of backlinks)
Does the domain authority, solely measured in the overall quality of backlinks, influence the value of a link?
Peter van der Graaf: “A broad an trusted linkprofile is important for you and sites linking to you.”
Ralph Tegtmeier: “Not if they're trashy links. If they're strong, yes.”
Eric Ward: “But...not 100% of the time.”
Jim Boykin: “The trust a site has based on backlink pattern I believe is very important.”
André Scholten: “A domain with good quality backlinks is very valuable link source.”
4.4
High influence
on the link value
high agreement
 
02. Age of domain
Does the age of the domain (with age as in registry date) have an effect on the value of a link?
Jim Boykin: “I'd much rather get a link from a site registered in 1995 that has 100 quality backlinks, than get a link from a blog registered in 2005 with 1000 quality backlinks.”
Eric Ward: “Unless it was an old crappy site to begin with. If the content was junk, ten years later it is simply aged junk.”
André Scholten: “The older the domain the more trust he gets.”
Maurizio Petrone: “Here I intended "age" as "first inception date" and "topic coherence over time" within a website, rather than "domain registration date"”
Ralph Tegtmeier: “Only indirectly in that aged domains may have developed more trust and authority which tends to upgrade their outlinks' impact.”
Hamlet Batista: “Google places a lot of importance to this.”
Peter van der Graaf: “Age of links to the domain help build its authority, and domain age is an indicator for possible old links.”
4.1
High influence
on the link value
mildly controversial
 
03. Relevant authority (in rankings on relevant keywords)
Can the domain authority, purely measured in the SERPs of the domain (or page) for link relevant keywords, influence the value of a link?
For example, does the page that links to your page about widgets rank for the keyword "widgets"?
Eric Ward: “Bingo. Keno. Yahtzee. Amen.”
Bob Gladstein: “I'd say that while the domain matters, the page matters more.”
Jim Boykin: “I don't believe so.”
Aaron Wall: “Lots of love during local reranking.”
André Scholten: “Good contextual links are better than offtopic links.”
Ralph Tegtmeier: “We see very strong indications that this is the case, yes.”
Hamlet Batista: “There is a document that explains re-ranking that could be in used in the search engines, but there is not enough data to confirm this.”
Debra Mastaler: “If I understand the question - pages ranking well get there (in part) as a result of their in bound link structure. High rankings pages are desirable to secure links from so yes, they can influence the value of a link.”
Arturo Ronchi: “The question is somewhat ambiguous. The ranking are constructed from numerous factors, those factors ARE influential on the value of a link. ”
3.9
Moderate influence
on the link value
somewhat controversial
 
04. Domain authority (in # of backlinks)
Does the domain authority, purely measured in the amount of backlinks, influence the value of a link?
Jim Boykin: “Sheer numbers no....type and quality are key.”
André Scholten: “The more backlinks, the more popularity a domain can pass through.”
Ralph Tegtmeier: "Purely measured in the amount of backlinks": Not if they're trashy links. If they're strong, yes."
Maurizio Petrone: “Can definitely be a good boost, but all depends on the link juice that is internally distributed to the page where your backlink is.”
3.1
Moderate influence
on the link value
controversial
 
05. Domain authority (in PageRank)
Is the domain authority, solely measured in the Google PageRank of the domain, an influential factor in determining the value of a link?
André Scholten: “Yeah, Pagerank still has some value.”
Eric Ward: “But...not 100% of the time.”
Bob Gladstein: “Not if the linking page is somehow cut off from that authority, but otherwise, yes.”
Jim Boykin: “I can never trust Google TBPR.”
Ralph Tegtmeier: “PageRank doesn't apply to entire sites or domains, only to pages. What's commonly referred to as "a domain's PR" will generally reflect that domain's index page PR value.”
Maurizio Petrone: “Every day, less.”
2.7
Moderate influence
on the link value
controversial
 
06. Domain authority (in rankings on irrelevant keywords)
Does the domain authority, purely measured in the rankings the domain (or page) achieves on link irrelevant keywords, influence the value of a link?
For example, does the page that links to your page about widgets rank for the keyword "flowers"?
Ralph Tegtmeier: “As far as I can discern, "domain authority" is an abstract value unrelated to topics or themes (or to keywords/search terms for that matter).”
Jim Boykin: “Again, don't believe so.”
André Scholten: “Popularity can be passed trough, no matter if the subject is relevant.”
Peter van der Graaf: “This increases so called trustrank, CNN links work wonders for new sites”
Eric Ward: “Sometimes yes, sometimes no. It will depend on the source site's previosuly earned trust.”
Debra Mastaler: “Preferable to be on topic but links sitting on authoratative offtopic sites pass quality link juice as well.”
Bob Gladstein: “Not if that's the only factor. If a given page's content is unique, it's going to rank well for something, even if that something is a five-word phrase. That alone isn't going to have an effect on the pages it links to.”
2.6
Moderate influence
on the link value
controversial
 
07. Domain relevance
Is the domain overall contextually relevant to the subject of the domain where the link is pointing to?
Eric Ward: “For higher end trusted content sites the domain name relevance is absolutely meaningless, and has to be.”
Maurizio Petrone: “We all knew how backlinks from Wikipedia helped when they weren't no-followed, and we can't say Wikipedia is contextually relevant to anything, within the domain overall.”
Jim Boykin: “Surely can't hurt.”
André Scholten: “Relevant links from a relevant domain are good.”
Ralph Tegtmeier: “No indication as yet that "domain themes" are a serious consideration. This would be very difficult for the search engines to implement anyway e.g. when dealing with multi-topic entities.”
2.4
Low influence
on the link value
somewhat controversial
 
08. TLD (.com, .edu, etc.) -based on TLD alone-
Does the TLD of a domain, for example .com, .in, .gov or .edu (and the TLD alone), have an effect on the value of a link?
Bob Gladstein: “Not if Matt Cutts is to be believed. Pages on .gov or .edu domains often carry a lot of weight, but that appears to be because such domains are often linked to and treated as authorities. I don't believe it's simply a function of the TLD.”
Barry Schwartz: “.govs and .edus I think do”
Eric Ward: “You can find worthless content on any TLD. The TLD alone is not enough to say the link value will be higher/lower.”
Peter van der Graaf: “Mainly ccTLDs effect ranking in Google.nl or Google.be with the same mydomain.com website. Edu value has diminished”
Hamlet Batista: “.edu, .gov top level domains happen to be linked by many trusted and high quality sources.”
Maurizio Petrone: “TLD *alone*? Not. Forget about it.”
André Scholten: “It's a known fact that .gov and .edu links are more appreciated than links from other tld's.”
Ralph Tegtmeier: “In compact with various other factors such as network distribution (think IP c lasses, etc.), yes.”
Arturo Ronchi: “Sure, give me a .gov link any time”
Aaron Wall: “Especially if you are trying to rank in those local markets.”
Joost de Valk: “.edu's and .gov's tend to have awesome backlinks, it's not in their TLD, it's in their backlinks.”
Jim Boykin: “I hate to say it, but I do believe google loves edu's and gov's....but not sure if they trust edu's with "~"'s in the url as much as an edu with the word "library" in the url.”
2.3
Low influence
on the link value
highly controversial
 
09. Alexa ranking
Is the Alexa ranking of a website of influence on the search engine value of a link?
Jim Boykin: “No way Jose.”
Bob Gladstein: “A site with a lot of authority may have a great Alexa rank, but I see no reason to believe that the Alexa rank itself has anything to do with the site's level of authority. Alexa rank is based strictly on traffic from users with the Alexa toolbar installed. It would be foolish for a search engine to give weight to something so heavily skewed.”
André Scholten: “I think the Scrabble value of the domain name is more valuable than the Alexa ranking.”
Ralph Tegtmeier: “Indirectly perhaps by influencing the crawling process.”
Maurizio Petrone: “Not directly. It does matter only if we consider the traffic of the website itself, and the perception that search engines have of this traffic.”
1.1
No influence
on the link value
high agreement
 

Dampening Factors

The last seven factors are dampening factors.
This doesn’t mean that these factors have a negative effect (e.g. as in a penalizing effect) on the link, it only means these factors might be able (or not) to make the link of lesser value.
Because this is not a research for link value dampening factors, only the most important factors have been included.

01. Robots.txt excluded page
Does it have an effect when the link is on a robots.txt excluded page?
André Scholten: “The page is not indexed, so the link stays unnoticed.”
Bob Gladstein: “Assuming the engine checks robots.txt before crawling the rest of the site, the exclusion of a given page should keep the spider from even requesting the URL.”
Eric Ward: “SERP only.”
Ralph Tegtmeier: “If robots.txt is honored, the page in question shouldn't get spidered and indexed in the first place. Obviously, it could still be found via third party inlinks which may impact its outlinks' value.”
Maurizio Petrone: “Absolutely. If a spider can't read the page, then it can't find the link. Simple, isn't it?”
Debra Mastaler: "pages blocked by NF can accumulate pagerank if they have links pointing directly to them”
4.8
High influence
on the link value
high agreement
 
02. Link is on penalized page
Does it have influence on the link when the linking page has been penalized?
(Penalized as in: the page doesn't score for it's title tag and/ or a similar query)
André Scholten: “Links on penalized pages are worthless.”
Ralph Tegtmeier: “As far as we can tell...”
4.5
High influence
on the link value
mildly controversial
 
03. Javascript link
Does it have an effect on the value of a link if the link is a javascript link?
Maurizio Petrone: “Pagerank should be passed if the URL is clear in the script, but at the current day crawlers don't really "interpret" javascript and so can't attribute weight to some types of javascript links.”
Ralph Tegtmeier: “As far as we can tell...”
Bob Gladstein: “SEs appear to be getting better at following links in javascript, but at this point the most one can hope for is that the URL of the target page is recognized and gets added to the crawl schedule. I don't believe such links carry any weight yet.”
Jim Boykin: “If the link can be read, I believe it has the same value.”
Eric Ward: “SERP only.”
André Scholten: “Search engines just can't get there crawlers read some javascript. There are some proves a full url in javascript code was followed, but I say it's worthless.”
3.9
High influence
on the link value
somewhat controversial
 
04. Redirect link
Does it have an effect on the value of a link if the link is in fact a (temporary 302) redirect?
Jim Boykin: “No negative effect...yet not positive effect either.”
Ralph Tegtmeier: “As far as we can tell...”
André Scholten: “A direct link is better than a indirect redirected link.”
Maurizio Petrone: “It really depends... Google itself has still problems handling duplicate content issues with temporary redirected links (and some affiliate link circuits like *cough* zanox *cough* are basing part of their strategy on this effect to rank their affiliate links). In many cases anyway, a 302'd link can pass all its potential link juice (expecially if the destination URL is written clear in the source URL).”
Hamlet Batista: “If the the redirect sets a cookie it could be interpreted as an affiliate link and get discounted.”
3.9
High influence
on the link value
controversial
 
05. Bad neighborhood links are present on linking page
Does the presence of links on the linking page that point to bad neighborhood websites have an effect on the value of the link that points to your website?
André Scholten: “It's not a context you want to be matched with by the searchengines.”
Ralph Tegtmeier: “Possibly.”
Hamlet Batista: “it depends on the quantity of bad links. A couple of bad links should not affect the value of the link”
Arturo Ronchi: “Presence alone wouldn't influence the link value. That a red light will flash besides Matt's desk is another thing though.”


3.6
Moderate influence
on the link value
mildly controversial
 
06. Paid Link triggers
Does the presence of paid link triggers, such as a TLA code, a PPP code or a ‘sponsored links’ section, have any influence on the link value?
(despite of the fact that you've paid for the link or not)
Hamlet Batista: “I have to think that these codes are part of Google new paid link detection technology.”
Ralph Tegtmeier: “As of very recently, this seems to be the case but too early to tell for sure yet.”
Bob Gladstein: “If the link is in that section of the page, it's absolutely going to make a difference. Otherwise, I think it depends on how much the paid links have affected the overall value of the page.”
André Scholten: “If Google decides to push the red button the link is devaluated at once.”
Arturo Ronchi: “I think that Paid link discovery is operated (partly) by humans. A "sponsored links" text alone one the page isn't enough to automatically dampen the link value.”
3.4
Moderate influence
on the link value
mildly controversial
 
07. Noindex page
Does it have an effect when the link is on a page that has a noindex meta tag?
Patrick Altoft: “As long as it doesn't have nofollow you are ok.”
Eric Ward: “SERP only.”
Ralph Tegtmeier: “Ideally, the page in question shouldn't get indexed in the first place. Obviously, it could still be found via third party inlinks which may impact its outlinks' value.”
Maurizio Petrone: “The noindex meta tag *alone* shouldn't be of any effect. It begins to be a factor of importance when it comes to traffic, findability and then linkability of the page when the link is on.”
André Scholten: “Value is passed on, so no negative effects at all.”
Arturo Ronchi: “This is a hard one. One would think that it would have the same score as the Robots.txt question. But I think that Google, Yahoo and Microsoft will treat this one differently.”
Joost de Valk: “Depends whether there's also a nofollow :)”
Bob Gladstein: “A page with a noindex meta tag can still be crawled, and links on it can still be followed, but those links are bound to carry less weight.”
2.9
Some influence
on the link value
highly controversial
 

Final Thoughts & comments

Here you go, you've reached the end of the list with link value influencing factors. This is the point where I want to thank all participants for sharing their opinions and special thanks to Arturo for designing this page.
Now that you've seen it all, there are three comments that I somehow had to include into this document. Consider them as a final thought.

Ralph Tegtmeier: “Link building research is indeed very important. However, an isolationist approach that views links as, well: isolated factors (no matter how many influencing variables you may slap on) is always problematic in terms of fundamental methodology and the results garnered thereby. Search results ranking and, by inference, SEO is a highly complex process governed by a multitude of interrelated non-linear factors more akin to chaos mathematics and fuzzy logic than to linear "Newtonian" or "Aristotelian" models of thought. Thus, any such research should be taken with a very big grain of salt.”
Michael Martinez: “Generally speaking, a link passes value (what we call anchor text and/or the equivalent of internal PageRank) if: 1) It is indexed; 2) It is on a trusted page; 3) It points to a page that is not banned or penalized; 4) It doesn't trip any triggers or filters”
Eric Ward: “Having built and studied thousands of links over the course of 15 years, I can say with 100% confidence that link value is and will always be relative. The links that are valueable to one site could be useless for another site. The approach that succeeds for one site can fail for another. The real art is in taking the science of link building and modifying and then applying it to each site as required for success.”
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