BitTorrent protocol is a decentralized method of distributing data. Instead of relying on a central server to distribute data directly to individual users, the BitTorrent protocol allows individual users to distribute data among themselves by exchanging pieces of the file with each other to eventually obtain a whole copy of the file.

     When using the BitTorrent protocol, every user simultaneously receives information from and transfers information to one another. Peers are individual downloaders or distributors of a particular file. A swarm is a group of peers involved in downloading or distributing a particular file. A tracker is a server which stores a list of peers in a swarm. Each swarm is unique to a particular file.

     The BitTorrent protocol functions as follows:

     First, a user locates a small torrent file, typically from a traditional search engine or from a torrent index site. This file contains information about the files to be shared and about the tracker, the computer that coordinates the file distribution.

     Second, the user loads this torrent file into a BitTorrent client, which automatically attempts to connect the tracker listed in the torrent file.

     Third, the tracker responds with a list of peers and the BitTorrent client connects to those peers to begin downloading data from and distributing data to the other peers in the swarm. When the download is complete, the BitTorrent client continues distributing data to other peers in the swarm until the user manually disconnects from the swarm or the BitTorrent client otherwise does the same.

     The torrent index sites are also target of copyright infringement lawsuits since they host the torrents which facilitate the infringement activities and therefore play the role of an accomplice even though the sites do not store any actual copyrighted material.