I am puzzled by the ability of the RIAA to even find out who is using the various file sharing networks such as Kazaa. I thought the whole point of peer-to-peer was to keep all information off of a central server or servers. How does the RIAA even find out who is downloading what? (Plus, I heard that with some of gnutella-based networks, it's all encrypted.) To issue all these subpoenas, they must have probably cause - where do they get that from?