This seems to much of a co-incidence... I checked the rankings of 3 of my websites that are affiliated to a dietary supplement. All have totally disappeared from the SERPS fo all my keywords! Matt Cutts of Google said on twitter a few hours ago that they were rolling out an anti-spam update. I always make sure my sites have good useful content. I don't consider them very spammy at all... Just wondering is it just me? Or are other people in the same boat? Thanks.