Breaching the Fuck Barrier
According to Steve Gilliard, the FCC has OKed "fuck" -- as long as it doesn't refer to "sexual or excretory activities". The ruling was in response to U2's Bono saying it at the Golden Globe Awards in January. The FCC said that while the word was crude, he was using it for emphasis, not to describe a sexual activity.
So I guess you can say something is "fucking awesome", but not "fuck you".