"Piracy" in music is similar to, but much more difficult to deal with, than bootleg movies. While there is a market for bootleg films, very often the DVD you get is grainy, was shot from behind a group of people, has lousy sound, etc, "pirated" or stolen music is often of a very high quality, making it more desireable and harder to put a stop to. And of course, music tracks or entire albums are less information than a DVD, so it is digitally faster to distribute.