How To Determine The Value Of A Link: Part I

Posted: 14 Apr 2011 05:30 AM PDT

Earlier this week we looked at a few seo concepts. We talked about the cat and mouse game of seo, how to think like a search engineer, and how competition affects your optimization and link building. I left things with the idea that different links have different values associated with them.

Today I want to talk about understanding the different values of links. Like the last post we’ll do this in more of a general common sense way and begin with the idea that a link is a vote or recommendation from one web page to another.

We’ll talk about trust and authority in links today and then next time we’ll look at anchor text of the links, link diversity, and offer thoughts for putting all this common sense to use.

Links as Votes or Recommendations

Google’s idea for using links to rank web pages came from scientific papers. The most important scientific papers are usually those cited most often in other scientific papers. Similarly links could be used as an indication of which web page was most important.

While the situation with links has certainly evolved and become more complex, the basic idea is still that links are how search engines find content and a link is a vote or recommendation by one web page for another.

In a simple election more votes for one side means that side wins. On the web if everyone could be counted on to only link to things they honestly recommend we might be able to rank pages based on which has more links.

Unfortunately we can’t always count on people to make honest recommendations.

We’re all biased in favor of our own sites, especially when money is on the line. Knowing that links are an important part of ranking many people try to increase the number of links pointing into their sites and pages in a way that really isn’t an honest recommendation or vote.

This brings us back to the cat and mouse game. More votes can’t win the election as people buy votes and stuff ballot boxes. Search engines need to do more than count all the votes. They need to sort through the votes to decide which ones are legitimate and which ones to throw away.

It isn’t a black and white thing either where votes are good or bad. It’s more a case of shades of gray where some votes (links) count more or less than others.

You also have to consider that each query typed is a different election, but the votes are collected en masse for all elections. Search engines not only have to decide how to value votes, but which election each vote applies to.

in this link = vote or recommendation concept, there are 3 different aspects of links that are looked at to determine the value of the link and which queries to apply the link to.

How much can the vote (link) be trusted?
Who’s doing the voting (linking)?
What’s being voted for (linked to)?

Can You Trust the Vote?

If you’re looking for a plumber you might ask friends and family who they use and their experiences. Your friends and family may not have expertise in plumbing, but you likely trust them to give you an honest answer.

However your cousin on your mother’s side gets a kickback from a plumber friend every time he can send his friend a new customer. Do you trust him when he points you to his friend? Maybe, maybe not. Maybe he’s an honest guy though maybe his recommendation is all about helping himself make some extra money.

Trust is important in links. Can search engines trust the motivation behind the link?

Internal vs external—What others say about you counts more than what you say about yourself. A link from another site is likely seen as more valuable than a link from the same site. Internal links are still an important part of seo and link building though.
Paid links—Is the link an honest recommendation or was the linker paid to add the link. Payment could be monetary or in trade a in a link exchange
Good and Bad neighborhoods—Does the site linking to you generally link to good sources? Trusted sources? Do the sites linking to them come from trusted sources? The company you keep says something about you.
Editorial control—Did you add the link yourself or did someone make an editorial decision to include the link. If a link can be acquired simply by filling out a form how much of an honest recommendation is it?
Nofollow—When we add rel=”nofollow” to a link we are saying we don’t necessarily trust the page on the other side of the link link and please don’t count it as a vote or recommendation for that page

The questions above all go to trust in links. There are a lot more questions you can ask, but when you’re thinking about whether or not a link is a good one to get ask yourself whether or not a search engine would consider that link an honest vote or recommendation for your page.

The more likely the link will be trusted, the more value it likely has in the eyes of search engines.

Authority: Who’s Recommendation is Worth More?

In a democratic election everyone has an equal vote. However when it comes to recommendations some recommendations count more than others.

Say you have two neighbors. One is a nobel prize winning scientist. The other is a plumber. The scientist holds several Ph.Ds, is well read, and in a general a very smart person. The plumber never went to college. He worked as a plumber’s assistant right out of high school and years later took over the business.

If you have a general question about how the universe works you’re probably going to ask the scientist. While there’s no guarantee he knows the answer, the odds are he’s going to be a better source than the plumber.

We expect the scientist to know a lot about a lot. However, if you have a question about how best to install a garbage disposal who are you going to ask? Probably the plumber. He may not know as much as the scientist about a lot of things, but he probably knows more about plumbing.

The scientist has general authority. The plumber has topical authority.

People ultimately have authority by displaying a certain knowledge or expertise. Assuming we couldn’t actually talk directly to them we might see people having authority based on how others suggest they’re an authority, For example the PH.Ds our scientist has earned are others saying he’s an authority.

It’s similar with links and websites. Those sites that have more and better links are seen as authorities. A site like Wikipedia is linked to from all over the web. Many different sites link to many different Wikipedia pages. The Wikipedia has general authority.

Sites like Smashing Magazine and Nettuts aren’t anywhere near as well known as the Wikipedia. Both sites are pretty well known in design and development circles though, and if you had a question about design or development you’d sooner check Smashing Magazine or Nettuts before checking Wikipedia.

While the Wikipedia has more general authority, both Smashing Magazine and Nettuts have more topical authority when the topic is web design or development.

PageRank (PR)—Is a measurement of general authority. It’s a very general measurement at best as the PageRank (PDF) you and I see is often out of date and it’s not shown to us on the same scale as Google uses internally.
PR only applies to Google. Other search engines have similar metrics, but they aren’t called PageRank.
PR is not topical authority—No matter how trusted or how authoritative in general sites like Wikipedia, CNN, and the Whitehouse are not go to sources when I need to answer a question about PHP.
Domain and Page—We can place authority in a single page or in an entire domain. We can say Wikipedia has a lot of general authority without making any judgement about any of it’s specific pages.
Some sites may have one or two great pages that are the defacto source on a topic, but the site in question may have little other valuable content or valuable content about the same topic.

When thinking about a link ask yourself how much authority does the page in question have. Is the page an authority. Is it located on a site you can trust? Do you trust the page and site in general or only on specific topics.

You can usually figure out who the topical authorities are simply by paying attention to your topic. Odds are the sites you would go to first for information are the same sites search engines see as authorities.

Summary

Link data accounts for a significant portion of search engine ranking engines. Outside of low to no competition keyphrases, links are a necessity if you want to rank well.

More links are not necessarily better. It’s more link value we’re after and a few high value links can outweigh many more low value links. While none of us knows exactly how search engines might value links if we think about a few basic concepts we can generally predict which links will be more valuable for our sites.

At the core a link is still a vote or recommendation by one page or site for another. The specifics get complex, but always keep the main concept of link = vote in mind. While there are a lot of different factors that make one recommendation more important than another, most of these can be grouped under a few major ideas.

Today we looked at factors of trust and authority, 2 key components of the value of any link. If a search engine can’t trust a link now or perhaps won’t trust it in the future, it’s not likely to contribute much to ranking. If a search engine things one page or site more of an authority (either general or topical) it likely places more value on links coming out of that page or site.

Next time we’ll talk about anchor text, the clickable words that make up a link, and what value information the anchor text conveys.