BitTorrent is a peer-to-peer file sharing protocol used for distributing large amounts of data. BitTorrent is one of the most common protocols for transferring large files, and by some estimates it accounts for about 35% of all traffic on the entire Internet^.

The protocol works initially when a file provider makes his file (or group of files) available to the network. This is called a seed and allows others, named peers, to connect and download the file. Each peer who downloads a part of the data makes it available to other peers to download. After the file is successfully downloaded by a peer, many continue to make the data available, becoming additional seeds. This distributed nature of BitTorrent leads to a viral spreading of a file throughout peers. As more seeds get added, the likelihood of a successful connection increases exponentially. Relative to standard Internet hosting, this provides a significant reduction in the original distributor's hardware and bandwidth resource costs. It also provides redundancy against system problems and reduces dependence on the original distributor.