We had an issue where our domain was blocked by adsense. For some reason we did not get a notifcation via email or the admin. Luckily we were large enough that my email to support reached a human and we worked it out...
Basically the algo's they use found a thread in our off-topic section that has the word 'jail bate' (sic) mixed in with the Title. Of course it was a parody thread with grown ups talking about not putting up with boys messing with their girls, the thread was basically clean of anything dirty, just a stupid title. Now I KNOW that the title probably was not the best on earth to have and possibly if I had seen it would have edited it, but the computer banned the domain and we had to remove the thread and then get approval back.
SOLUTION: We decided (and Google suggested) that our OFF TOPIC section with varying discussions would not run Adsense. The risk/reward of ads where people 'chat' all day and are regular members was not worth it, and also no real revenue there anyway, board regulars are not going to click.
So if any of you have a good topical/niche content forum, and an offshoot off topic area, look at removing the adsense there so you don't get banned for innapproriate language or pictures from members BS'ing all day.
Mike