Is there any good authoritative source of information on SEO practices that is backed up by data?

Question

Any google search for anything about SEO yields more articles than you can shake a stick at, but lot of the articles are out of date, many have conflicting advice and I just about none of them ever give any reasons/proof/data to back up their claims about what works and what doesn't.

Has anyone done any at least somewhat scientific tests to see what works and what doesn't (and ideally why?) or has anyone from Google released any non-basic information about best practices?

Really what I would love to do is A/B test different SEO techniques, but the time lag and sheer number of variables makes it very difficult. Has anyone ever tried this type of thing? (And published their results?)

Answer 1

http://www.google.com/webmasters/

http://www.google.com/support/webmasters/

Answer 2

SEO is the oddest thing. You can go by Google's recommendations that Jeff listed, but they list stuff on how to make your site not suck, they do not list stuff on how to make your site really good. The best guide I have found is by SEOMoz called "Beginners Guide To SEO"

http://www.seomoz.org/article/beginners-guide-to-search-engine-optimization

SEOMoz is actually known for their sandbox testing of techniques, so they are as close to an expert that you will find.

Answer 3

Would also keep an eye on Matt Cutt's (from google) blog http://www.mattcutts.com/blog/, he spends a fair amount of time answering readers questions.

Answer 4

If someone is putting SEO advice online, and that advice is not easy to find with Google, then it's bad advice, whether it's backed up by research or not. Stands to reason: if the author was any good at SEO then you'd have found their page by now.

Answer 5

StackOverflow is a Page Rank 6 ... SingingEels has a PR of 4 (twas 5... I cry). Both, I can tell you, comes from content... content, and content.

Good, quality, original content. Also, notice that the questions are in "h2" tags, and the answers are in "p" (paragraph) tags. This leads to point #2 -> semantic markup.

While SO also uses crappy tables for the design (Jeff!!!), the markup that counts (the content) is done well.