What Ever Happened to Peer-to-Peer Systems?

Peer-to-Peer (P2P) systems became famous at the turn of the millennium, mostly due to their support for direct file sharing among users. By the 1980s, the music industry had evolved from selling analogue vinyl records to digital compact disks, but with the introduction of lossy data-compression techniques such as the MP3 coding format, it became feasible to upload/download music files among users' personal computers. Still, content had to be catalogued and found, and P2P systems emerged to provide that functionality. Some early systems, such as Napster and SETI@Home, exhibited a mix of P2P and classic client-server architecture. Gnutella and Freenet, the second generation of systems, provided a larger degree of decentralization.