I'm a little bit paranoid after I was surfing on a webpage which was "boundary" - legal. (got there directly by google.) There i could not only see an howTo build a bomb... I also saw a picture of my sis in a "Wanna play facebook tetris" add. WTF... It was really weird. I have no idea why facebooks advertise on such pages. I logged in facebook and logged out again, also changed my IP and got back. The same add with a different facebook friend showed up. I don't thrust them anymore after that.