Clay Shirky is a smart guy, and he's figured out something new again:
[Governments have] been terrified of losing surveillance powers over digital communications generally, and one of their biggest fears has been broad public adoption of encryption. If the average user were to routinely encrypt their email, files, and instant messages, whole swaths of public communication currently available to law enforcement with a simple subpoena (at most) would become either unreadable, or readable only at huge expense.
[...] The music industry's attempts to force digital data to behave like physical objects has had two profound effects, neither of them about music. The first is the progressive development of decentralized network models [and the second] is the long-predicted and oft-delayed spread of encryption. [...] Because encryption is becoming something that must run in the background, there is now an incentive to make it's adoption as easy and transparent to the user as possible.
[...] People will differ on the value of this change, depending on their feelings about privacy and their trust of the Government, but the effects of the increased use of encryption, and the subsequent difficulties for law enforcement in decrypting messages and files, will last far longer than the current transition to digital music delivery, and may in fact be the most important legacy of the current legal crackdown.