Answers.com released a press statement warning investors that traffic has fallen 28 percent since Google's August algo update. there are references to the algo update here http://blog.searchenginewatch.com/blog/070803-162041 http://blog.clickz.com/070803.html
I notice my site from #6 to #2 ... consider big different to me...and my other site which #2 before this now in #11.
One of my keyword at 7th of 1st page and the other one at 932nd of ... page. Anyway, my site PR still ZERO.
I have seen a lot of change on some of my sites too, a few have disapeared and i cant even find them, Woc
Google always change their algo and updates SERP daily. But I don't think that this a big algo update. Build more links in order to have a better SERP position.