Napster, KaZaA and most of the initial wave of p2p sharing had centralized servers which were required for coordination. That's why it got shut down. The record

Napster, KaZaA and most of the initial wave of p2p sharing had centralized servers which were required for coordination. That's why it got shut down. The record companies sued the companies behind them and won, forcing them to shutdown their networks. The second wave of Gnutella and all of the various BitTorrent clients was decentralized. No single entity controlled the network so there was no single point of failure. Record companies and movie studios came after individual nodes, but were never ever to shut down the network. However, no one ever invented a great way to do search and discovery on top of BitTorrent, so we've always had centralized servers for that piece.