Well, first I would ask you to prove that with all other factors eliminated, the top ranking sites for a term have less relevant inbound links then the rest of the competing pages (which would be very difficult to do). If you read this article http://www.webworkshop.net/googles-big-daddy-update.html about one of Google’s overhauls a few years ago called “Big Daddy,” it quotes Matt Cutts, a senior software engineer from the company. In it he talks about Google’s new algorithms for checking link relevancy and the search engine’s aim to clean out sites ranking due to excessive reciprocal and non-relevant links. So, yes, I think it’s safe to say this is a factor.

Not that I need to verify something that you arbitrarily suggest accounts for 20% of search engine listing rank yourself, but I am also conducting an independent study testing different proposed ranking factors that SEO “specialists” have put out there, some preliminary results can be read here http://www.warrensamu.com/2009/06/29/how-people-use-search-engines/ . Of 19 top ranking sites analyzed, on average, 62% of the listed Google inbound links on the first page were relevant for each site, suggesting that link relevancy plays a role. I cannot really use the scientific method here, I have yet to see a similar study, but I do know that almost all SEO webpages I come across, some combining the overall opinions of hundreds of SEO consultants, state inbound link relevancy as a high factor to consider.

SEO is not a science, it’s more of an art, and it’s also guess work. We can only make the best estimate based on experience, shared or otherwise. Search engines constantly update themselves, sometimes change the rules, and only their programmers truly know the insides of their algorithms.

Utter nonsense. Prove it.

Relevance accounts for only around 20% of the factors taken into account for a link. Are you telling us that all those sites at the top of google page one with hundreds of non-relevant links have relevant links hidden away somewhere?