Since there are already plenty of great articles out there exploring how to build good links, I'm using this series of articles to dive into why links matter when it comes to search engine optimization. The thinking here is that by understanding why the search engines value the things that they do, you'll be better able to put link building techniques into place that will serve your site both now and in the future, even after the search engines update their algorithms further.

In part one of the series, I explored the idea of links as the threads of the web, helping both search engines and humans find their way from one site to another. In part two I'll explain why search engines look to links as part of their attempt to replicate human judgement so that they can determine the content of the web site or web page.

Links Give Your Site Context

As I explained in part one of the series, search engines spiders are just computer programs. They aren't capable of thought. While they are programmed by human beings, they're still just computers operating on letter and numbers and patterns. As such, they have to look for patterns to find out how to make judgements about that web site. That includes figuring out the content or context of a web page.

While most people understand that search engines are able to note patterns in terms of the keywords and keyword phrases that appear on a web page, it's also important to understand that search engines look for patterns in the text of the links to your site.

Yes, some links simply read "click here" or "more" or some other random set of words, but most of the time, link text is used to describe the page that is being linked to. Human beings observed that pattern of action, so they programmed search engines to look for it as well. That's why search engines rely on link text to determine the content of your web page.

Basically, incoming links help the search engine to understand how other sites view your site. Chances are good that if 80% of the links to your site include the phrase blue widget, your site probably talks about, sells or otherwise is related to blue widgets.

Another thing to consider is that search engines are beginning to move toward latent semantic indexing. (Simply put, that means that they would be programmed to understand that an automobile and a car are the same thing, or that a Volvo, a Honda and a BMW are all types of cars.)

How does this relate to link building? Well, since different web sites will use different link text when pointing to a site, semantic indexing would allow a search engine to look at the wide variety of incoming links text and to then categorize the site as being about a particular topic.

For example, a site that sells used cars might have incoming links that used phrases like "pre-owned Lexus" "Certified used GMC truck," "low-mileage Honda" and "late model miata."

When considering how links give a site context, it's important not to forget about your own internal links that are used for navigation. Your navigational links will help the search engines to understand how YOU see your site, so paying attention to the link text that you use internally is just as important as paying attention to the link text of any incoming links that you build.

In part three of the series, I'll explain how search engines use links to validate a site's authority and to determine how well respected it is by Internet users.

Discuss this article in the Small Business Ideas forum.

March 15, 2007

Jennifer Laycock is the Editor of Search Engine Guide, the Social Media Faculty Chair for MarketMotive and offers small business social media strategy & consulting. Jennifer enjoys the challenge of finding unique and creative ways to connect with consumers without spending a fortune in marketing dollars. Though she now prefers to work with small businesses, Jennifer’s clients have included companies like Verizon, American Greetings and Highlights for Children.

Search Engine Guide > Jennifer Laycock > Why Links Matter - Part 2