Peer-to-peer sites (P2P) involve peer-to-peer networks, which are designed to work differently that other networks. In peer-to-peer networks, there is not a central site to which many go to obtain information and products. Rather, each participant shares resources and consumes resources from the network formed by all participants. Four main types of peer-to-peer sites have developed: those devoted to file sharing; those used for bioinformatics; those adapted for telecommunications; and those devoted to lending.
File sharing, both legal and illegal, is one of the chief uses of peer-to-peer sites and networks. BitTorrent, Inc., the company owned by Bram Cohen who developed the popular peer-to-peer file-sharing protocol BitTorrent, has licenses to distribute content including films, music, television broadcasts, and software, including for example, World of Warcraft®. The LionShare project—whose participants include the Massachusetts Institute of Technology (MIT), Pennsylvania State University, and Simon Fraser University—has the purpose of file sharing between and among educational institutions around the world. Its home is on the Penn State website.
There are some very famous peer-to-peer sites that have been loci of accusations of copyright infringement and illegal music and movie downloading. One of these is The Pirate Bay—sold in July, 2009 to Global Gaming Factory after its four founders were convicted of copyright infringement in April 2009, and slated to morph into a copyright-respecting, legitimate business. Another is Kazaa (formerly KaZaA), which was sued for illegal file sharing and paid $100 million in restitution to the music recording industry and has changed its model to a subscription service. Napster was a peer-to-peer file sharing service for mp3 files, that ran for two years until a court order shut it down in July 2001. The Napster brand also reemerged as a paid service.
Bioinformatics is another use to which peer-to-peer sites have been put. Bioinformatics, which is the harnessing of information technology to process huge amounts of information in molecular biology, has experimented with using peer-to-peer networks to run large programs. The telecommunications use of peer to peer sites is most notably carried out by Skype, which was known in early days as “Sky peer-to-peer” or “Skyper.”
Peer-to-peer lending, also called person-to-person lending or social lending, is the name given to lending that happens between people without the involvement of a financial institution. Peer-to-peer lending may be secured or unsecured, and is run from peer-to-peer sites in at least some cases.