After having an SEO research Fri afternoon, came another superb article courtesy of Moz.
If you ever wanted to know the complete low-down on all the current thinking on how to rank your website, or what factors are stopping you from ranking, it's all here!
It's long, it's full on, and has as much information as you will ever need.
Google Ranking factors - Northcutt
If you do read it, be interested to hear any views, anything you don't understand, disagree with?