deadsea - 11:46 am on Dec 14, 2012 (gmt 0)

I think Google's stemming is throwing sites into the mix that might not rank because of keywords or even backlinks/anchor. Is there any evidence of this MB?

MB's post is very insightful. His observations match mine. In my opinion "bounceback rate" is biggest driver of rankings. How many users return to Google unsatisfied looking for another site or modifying their query.

Its not just stemming that is throwing additional sites into the mix. Google is also putting in sites that have a subset of the keywords you are searching for. So much so that using Google search without "Verbatim" turned on is painful to me. This has only been the case for about 2 years now.

The personalization of the SERPs based on location, history, and profile also throw a ton of new sites into the SERPs.

We know that Google is trying out more sites than ever before. You visit a SERP on two different computers and you are almost guaranteed not to see the same listings these days.