We all know the importance of having the right anchor text in a link pointing to a page we want to optimise for a specific keyword.
It is a common assumption that the more back-links with anchor text containing our keyword, the better. This of course has created a business in link-building that many SEO experts and customers consider as a matter of quantity over quality.
Most knowledgeable SEO experts know it is above all a matter of quality of links but do we all know what follows? This is quite an eye opener, thanks to Bill Slawski and his great blog “SEO by the SEA”, one of the must read SEO blogs on the web.
Recent patents applied by Microsoft and earlier ones applied by Google (source, Bill Slawski, “How a Search Engine might Weigh the Relevance of Anchor Text Differently“) imply that the relevance of anchor text links might be weighed differently by search engines based upon the relationship between the pages or sites where those links are located or where they are pointing towards.
In the case of mirror sites, it seems quite logical for a search engine to reduce the weight of repeated and similar outgoing links.
What is really interesting is the effort put into detecting the relationship between two different websites that link to your target page. The idea is to detect whether these two external sites are under the control of the same or related users. The obvious symptom of this would be that those two sites have a substantial number of same or similar anchor text links pointing to the same destination.
Lesson: always vary your anchor text in order to leave not only a human footprint but also to reduce the impression of linking pages being related.
Another situation described in the patent application is when anchor text links appear to be purposely created to boost the search rankings of a destination page. This is a step forward towards trying to establish relationships between linking sites in order to identify is someone controls both of them. The weight of anchor texts in this configuration (related or dependant sites that point to a same page) is reduced.
Even two pages belonging to two different sites and linking to your target page, could be examined in order to see if they also link to other similar pages and thus there could be probable dependence or relationship between them.
Lesson: vary your outbound links so as to create differences and that two linking pages do not link to exactly the same external pages, with the same anchor text.
Other pages in the same linking website could be examined in order to establish whether more pages from this linking website also link to the same target website, this reflects a clear site relationship and will reduce the weight of those anchor text links.
Lesson: creating your network of blogs or press agencies can be useful but do not use them to point exclusively to your own money sites, be generous with outbound links pointing to sites you are not related too, we recommend authority sites on the topics of your site (national newspapers, Wikipedia, etc.).
The implications for SEO practitioners are enormous and those using blog networks and related sites in order to boost rankings of their money sites must rethink the relationship between linking pages and the sites they belong to.