Google has completely rewritten their Quality Ratings Guideline (this is the resource that their team of quality raters uses to rate websites). The brand new version was leaked online and although Google hasn’t confirmed (or denied) that this is the actual document, it seems legit.
This new document which has only been written about by a couple people so far has a ton of interesting information in it.
The document is 3 months old and here is some of what it covers: