With the recent google update about 20 or so sites dealing with the same topic (but different regions) were de-indexed. The strange thing is that my sites that I never listed in the dashboard of Webmaster Tools were fine and are still indexed. Has this ever happened to anyone else? I've always been suspect of the close connection of using all of google's services. On a related note, someone I know has a similar type of website that isn't very pretty, updates every couple months, and doesn't use anything related to google except adsense and has ranked number one on google for years.
I have a strange sensation that you are right. They are using the info we help them to get against us. I'm now testing some reporting tools in order to give up on analytics. I'll maintain adsense till something similar appears.