The producer of a mashup album that combined the Beach Boys' Pet Sounds and the Beatles' Sgt. Pepper's Lonely Hearts Club band has been threatened with a multi-million-dollar lawsuit by EMI, the Beatles' music publisher. EMI has also demanded that they turn over the IP addresses of the hundreds of thousands of people who downloaded the mash-ups, presumably so that EMI can sue them for dammages.

Forget file sharing, derrivative works are the real threat to the established players.