As I don't get many clicks on my adsense blocks, I rarely check the account. Last night I decided to try a block on a new blog...and found I had clicks coming from hard core porn sites!
This was really nasty stuff. I had my account set to let any websites place ads, needless to say it's changed now - but do check your settings!
I'm assuming someone did it to get me an adsense ban? Why the hell can't people just live and let live!?