If you're using revenue sharing sites then read the following blog Continued at: http://www.searchenginepeople.com/blog/adsense-closed-account.html
"The irony to this was that the termination was not a result of having AdSense on any of my self hosted websites but was because I associated my AdSense account with a couple revenue sharing websites such as Squidoo and Hubpages, which by default, encourage their writers to add their AdSense account for a share of the profits." This article is full of sxxx how come the author can be trusted? What does he know about anything? Like if adsense would tell him more details than what they tell other banned publishers, that is nothing at all? So it's pure speculation from his part and nothing more, but nowhere in the article does he say so.. He writes as if he knows. Well he knows nothing for the simple reason that adsense doesn't give any details in its ban email for invalid clicks and not even in the appeal email.