In the original simplified Google Page Rank algorithm all links were treated equally, no matter where they were on a page. This meant that a sidebar link, or footer link would hold the same value as a link within content.
In-content links weren’t arguably as valuable to rank a website at this point in the Google algorithm, mainly because a content-based link would typically only be one link. Whereas a site-wide link within a side-bar blogroll or footer would be many links. This meant that less focus was placed on building unnatural links within content, as it was much more effective to build other types of links.
As Google became better at understanding links, they were able to update how Page Rank was calculated. As Google were now able to identify different types of links using technology, they no longer had to treat all links equally. In a patent filed in 2004 the reasonable surfer model outlined a different Page Rank weighting (commonly referred to as link juice) for links with a higher chance of being clicked. For more information about this read this article by Bill Slawski.
As a direct result there was a shift in link building toward in-content links, and away from site-wide links in footers and side-bars.
It took a while, but Matt Cutts finally confirmed that Google doesn’t pay the same level of attention to all links on a page.
Different people have slightly different definitions of a content link, but in summary it is a link which is positioned within some form of machine-readable text content. This could be, for example, in an article, blog post, a blog comment, or anything where content is present. Content can vary widely so there isn’t really a definitive list.
As mentioned before in this guide, spammers always go for the quickest, easiest route to get results. As spammers had discovered in-content links had more power than other types of links, they realised the easiest way to get in-content links was to leave comments on websites, forums and blogs. Using software such as XRumer it was possible to create lots of in-content comment links, quickly and, importantly, with minimal effort.
However, the problem Google faced was that they had to be able to tell the difference between different types of content links. After all, an editorially-given link in the content of an article shouldn’t carry the same influence as a user-generated comment which has had little to no editorial control!
In early 2005 (a short while after the reasonable surfer patent), Google introduced the nofollow attribute for Webmasters to protect their websites against spam. The theory being that if nofollow attributes were added to all the links generated by users, it wouldn’t give them any SEO benefit, so potential spammers wouldn’t spam a website. Slowly this allowed Google to help understand the differences in content links versus comment links.
As comment link building stopped being as effective, efforts shifted towards other new ways of getting content-based links, but this time within the content (article, blog, etc.). There was one big problem with this; it suddenly became less automated, scalable and ultimately profitable to get links!
Ways to get links in-content now included;
- Ad hoc paid links
- Article directories
- Guest blog links
- and, perhaps the most effective of them all – link networks
It is important to understand the difference between the position of links on a page, combined with the type of link. Understanding the differences will help you understand how a link came to exist, and ,chiefly, if it is natural or unnatural.