I guess Brett's has something against Adsense, he keeps calling these threads Adsense Farm while everyone esle is referring to it as content farm... He's already named three threads that way, best be careful or he'll trip some kind of spam filter. ;)
I'm not getting that 20 websites to 3 mention... If Google really goes after the large content farms, there should be more winners than losers.
I can certainly emphatize with many of those on the losing end of this change. We started our site in March 2004, which was the same month Google rolled out the sandbox. I just looked back at our stats. Google didn't let us out of the sandbox until February 2006 - 23 months later.
Outsiders looking at this thread need to be careful about intepreting the results of this change. Posters here will NOT be a representative sample of webmasters. They will be those that were affected negatively by the change.