Gnutella

Gnutella is a free, open source project to create a true peer-to-peer file sharing network. Such a network would be a fully distributed alternative to semi-centralized systems like Napster. To date (February 2000), Gnutella has not achieved widespread success, due primarily to problems of scalability.

Sometimes the word 'Gnutella' refers not to a particular project or particular piece of software, but to the open protocol used by various clients. Since new clients are under development all over, and since a new protocol is apparently on the way too, it is hard to say what the word 'Gnutella' will mostly stand for in the future.