The Art of SEO, 2nd Edition

How Links Influence Search Engine Rankings

The concept of using links as a way to measure a site’s importance was first made popular by Google with the implementation of its PageRank algorithm (others had previously written about it, but Google’s rapidly increasing user base popularized it). In simple terms, each link to a web page is a counted as a vote for that page, and the page with the most votes wins.

The key to this concept is the notion that a link represents an “editorial endorsement” of a web document. Search engines rely heavily on editorial votes. However, as publishers learned about the power of links, some started to manipulate them, through a variety of methods. This created situations in which the intent of the link was not editorial in nature, and in turn led to many algorithm enhancements.

To help you understand the origins of link algorithms, the underlying logic of which is still in force today, let’s take a look at the original PageRank algorithm in detail.

The Original PageRank Algorithm

The PageRank algorithm was built on the basis of the original PageRank thesis (http://infolab.stanford.edu/~backrub/google.html) authored by Sergey Brin and Larry Page while they were undergraduates at Stanford University.

In the simplest terms, the paper states that each link to a web page is a vote for that page. However, votes do not have equal weight. So that you can better understand how this works, we’ll explain the PageRank algorithm at a high level. First, all pages are ...