Gnutella is a large peer-to-peer network which, at the time of its creation, was the first decentralized peer-to-peer network of its kind, leading to other, later networks adopting the model. It celebrated a decade of existence on March 14, 2010 and has a user base in the millions for peer-to-peer file sharing. In June 2005, gnutella's population was 1.81 million computers increasing to over three million nodes by January 2006. In late 2007, it was the most popular file sharing network on the Internet with an estimated market share of more than 40%. The first client was developed by Justin Frankel and Tom Pepper of Nullsoft in early 2000, soon after the company's acquisition by AOL. On March 14, the program was made available for download on Nullsoft's servers. The event was prematurely announced on Slashdot, and thousands downloaded the program that day. The source code was to be released later, under the GNU General Public License (GPL).
Contributions by FrYGuY, Bpringlemeir, and Easyas12c.
iTunes is not a peer to peer file sharing service.