First they killed Napster, just recently they killed Grokster, and now they are prosecuting bit torrenters.
That's going to prove problematic. Many legitimate shows are distributed via Bit Torrent (see TWIT or diggnation or CommandN) so attacking the software won't work. And it's peers to peer so locating the exact person to prosecute for distributing is going to be very, very difficult. That leaves attacking the tracker sites which put the peers together and some of them are located in places where they can't be touched. In fact, Pirate Bay even publishes the threat letters it receives and makes fun of them.