I can't post the link because I'm a new member but I just stumbled upon a really useful analysis of the Google algorithm change history by SEOMoz, which you guys probably already recognize. For those of you just getting into SEO, SEOMoz is the leader of SEO information, really great resource. It should be relative easy to find, just google search the keyword: seomoz algorithm change history. Dates back many years and was a really interesting read for me, check it out. Oh, if someone wants, they can post up the link so that people dont have to manually google search it. Cheers