I heard this on the other day. I was driving at the time, so I don't remember it exactly, but it started with a girl arriving at a friend/acquaintance's house. The mom let her in and told the other girls she was there.
Immediately one of the girls spoke up, saying things like, "Oh, look who showed up. I didn't think you'd show your ugly face here again after the dumb things you said last time. God your fat! Oh, and have I mentioned your zits? You're such a waste of space. I wish you'd just go kill yourself."
Then the announcer-voice came on and said, "If you wouldn't say it face-to-face, don't say it in cyberspace."
I thought it was a great commercial. Harsh enough to get my attention, and very blunt in its message.