File sharing P2P networks

Gnutella

from: www.gnutella.co.uk/about/

"Gnutella is the name of protocol that allows people to exchange files over the internet. You connect to the Gnutella network (GnutellaNet), using a Gnutella client. The original Gnutella client was developed by Justin Frankel and Tom Pepper at Nullsoft. AOL quickly closed the site down, but not before thousands of people had downloaded it."

Gnutella is decentralised

Among other advantages: "Ability to define your own internal network with a single exit point to the rest of the internet makes it difficult to block access to GnutellaNet".