It's a very grey area. My opinion is, trying to stop the distribution of files in a legal manor is a waste of time. It's like speeding on roads. Most people do it, Some unfortunate people (often stupid) get caught, but does it stop other people doing it ? NO. Also, Every torrent site you get shut down, 100 more will appear.

There needs to be a more intelligent design to stop the distribution of files without the need for DRM/rootkits/monitering peoples traffic that doesnt also stop the owner from copying the files to their personal mp3/mp4 players or other computers.