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 doesnt 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

 

Top 10 Most important factors

1. Robots.txt excluded page (DF) - 4.75
2. Anchor text - 4.56
3. Link is on penalized page (DF) - 4.50
4. Page authority (in inbound links) - 4.38
5. Domain authority (in quality of backlinks) - 4.38
6. Amount of outbound links on page - 4.25
7. Total amount of links on page - 4.06
8. Age of domain - 4.06
9. Relevant authority (in rankings on relevant keywords) - 3.94
10. Javascript link (DF) - 3.88

Top 5 Most agreed factors

1. Alexa ranking
2. Robots.txt excluded page (DF)
3. Domain authority (in quality of backlinks)
4. Page relevance (words only)
5. Number of links

Top 5 Most controversial factors

1. TLD (.com, .edu, etc.) -based on TLD alone
2. Type of link (image, text)
3. Domain authority (in PageRank)
4. Domain authority (in rankings on irrelevant keywords)
5. Target page (where the link points to) location

Categories of linking factors

Link Factors: Anchor Text • Age of the link • Type of link • Surrounding text • Number of links • Location on page • Reciprocity • Target location • Location in source // On-Page Factors: Page authority • Amount of outbound links • Total amount of links • Page authority • Relevance of outbound links • Age of page Page relevance • Quality of outbound links • Amount of non-linking content • Page URL • Page relevance • Page authority • Last date of edit • Page type // On-Domain Factors: Domain authority • Age of domain • Relevant authority • Domain authority • Domain authority • Domain authority • Domain relevance • TLD • Alexa Rank // Dampening Factors: Robots.txt • Penalized page • Javascript link • Redirect link • Bad neighborhood links • Paid Link triggers • Noindex page

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.
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