Rand Fishkin and the SEOMoz team have put together an updated version of their popular SEO Ranking Factors document. This time around they've cut the data from more than 100 factors to just 55, but there's still plenty of easy to digest opinion and input from nearly three dozen search marketers.

The format of the document has also been updated, making for a much easier to digest collection of data. You'll find that each factor includes a description, a ranking importance (based on votes by the contributors), the level of disagreement about the factor and some selected comments from the contributors.

In Rand's words:

This document represents the collective wisdom of 34 leaders in the world of organic search engine optimization. Together, they have voted on the various factors that are estimated to comprise Google's ranking algorithm (the method by which the search engine orders results). The result is a resource of incredible value - although not every one of the estimated 200+ ranking elements are included, it is my opinion that 90-95% of the knowledge required about Google's algorithm is contained below.

It's important to note that this document won't tell you HOW to optimize your site, it instead aims to help you understand what you need to focus on. In other words, find out what you might need to change and then take advantage of other resources (like the newly updated Small Business Guide to Search Engine Marketing) to learn how to make those changes.