P2P folk have a new self-help device: PeerGuardian. The program blocks IP addresses, and prevents snoopers from downloading traded content in order to determine if it is copyrighted. In short, it throttles unwanted monitoring of network activity.
PeerGuardian protects freedom and privacy on the Internet, a feature which makes the software a valuable self-help tool. But there is a danger here, too. Given the RIAA's trigger-happy attitude, I can very easily imagine someone from the music industry making the argument that PeerGuardian is guilty of contributory infringement because the company "materially contributes to the infringing conduct of another." The best defense, I suppose, is the Sony defense -- PeerGuardian is a dual use technology, and serves to protect privacy rather than facilitate illegal file trading. But if the court disagrees, and (wrongly) rules that protection of copyright holders outweighs privacy concerns, then privacy and the Internet will be harmed. Temporary gain might result in long-term damage.
Ideally none of this will come to pass, but it is something worth thinking about as this technology is adopted into widespread use. Wired has a write-up of the software here.