An old idea of mine was to produce a wiki for SEO. Happily, someone else has taken on the project (as I really never got around to it). It's called Organic SEO and it's got a fairly good basic walkthrough of the principles of optimization already. I urge readers to hop on over, see if they can throw a few contributing paragraphs at the wiki, and watch it grow. It certainly would be nice to have our own SEO wikipedia that can answer beginning or even advanced questions with authority.