When Napster was busted by RIAA, I predicted (just in conversations with friends) that file sharing would just go underground.  I figured people would create private networks that would enable file sharing well below the radar of RIAA or any other industry agency.  I don’t follow P2P closely at all, so Tubes might not be the only service of its kind, but it’s the one I just found out about.  When people are sharing files through private, invitation-only, trusted networks, what is the RIAA going to do if they can’t get in?  Tubes only runs on Windows.