Boing Boing’s Cory Doctorow explains it all for you, lucidly:

[I]t can never work for movies, TV shows or music, because in the case of “copy protection” the receiver is also the person that the system is meant to guard itself against.

Say I sell you an encrypted DVD: the encryption on the DVD is supposed to stop you (the DVD’s owner) from copying it. In order to do that, it tries to stop you from decrypting the DVD.

Except it has to let you decrypt the DVD some of the time. If you can’t decrypt the DVD, you can’t watch it. If you can’t watch it, you won’t buy it. So your DVD player is entrusted with the keys necessary to decrypt the DVD, and the film’s creator must trust that your DVD player is so well-designed that no one will ever be able to work out the key.

This is a fool’s errand. Because the DVD player has the key, it’s always possible that it can be extracted by academics, hardened hackers – or just kids who are in it for the glory.

And the punchline:

This means that ultimately, DRM only effects people who buy media honestly, rather those who nick, borrow or cheat their way to it. In turn that means that the people who ultimately bear the inconvenience, cost and insult of DRM are the paying customers, not the pirates.