Rand Fishkin of SEOmoz recently posted a presentation on slide share named The Evolution of Google's Rankings. It was from a presentation he gave in the Searchmetrics Partner Meeting a couple months ago.
The slides take you through what ranking factors are most important to Google over the years, based on Rand's experience. It is broken down as follows:
- 1999 - 2002 : On Page SEO & PageRank
- 2003 - 2005 : Anchor Text, Domain Names, etc.
- 2006 - 2009 : Domains, External Links, Quality Raters
- 2009 - 2011 : Twitter Social Data, Brands, User Behavior, etc.
In fact, the whole thing was posted on YouTube, here they are:
There is a thread at WebmasterWorld discussing the presentation. Most find it dead on, but as CainIV said, "I think this makes to look at in terms of aggregate factors that those interviewed believe are in play across a large number of genres."
Forum discussion at WebmasterWorld.