This makes for interesting reading (although it's by moz): Code: http://moz.com/search-ranking-factors/survey
The problem with Moz is that it's like Matt Cutts, good at talking for hours not saying anything important but sounding really smart. When I first started out doing SEO, SeoMoz was my bible. I was hooked on Fiskin's blackboad friday. But, after a while I realized that the only benefit of this type of learning is that it's meant to teach you how to think SEO, and how to understand white hat marketing on a theoretical level. Applying that to the real world is a totally different cup of coffee. And that's undestandable if you only get one little valuable APPLICABLE information once in 1000 words. So, the bottom line is, don't take all Moz says as the absolute truth because it's far from it.