The Pirate Bay is a Swedish website that indexes and tracks BitTorrent ("torrent") files. It bills itself as "the world's largest BitTorrent tracker" and is ranked as the 98th most popular website by Alexa Internet. The website is primarily funded with advertisements shown next to torrent listings. Initially established in November 2003 by the Swedish anti-copyright organization Piratbyrån ("The Piracy Bureau"), it has been operating as a separate organization since October 2004. The website is currently run by Gottfrid Svartholm ("anakata"), Fredrik Neij ("TiAMO") and Peter Sunde ("brokep").

On 31 May 2006, the website's servers, located in Stockholm, were raided by Swedish police, causing it to go offline for three days. The Pirate Bay has also been involved in a number of lawsuits, both as the plaintiff and as the defendant. The website sued several media companies after emails from anti-piracy company MediaDefender were leaked online which revealed that the company planned on using illegal methods to take down The Pirate Bay because legal means were unsuccessful. According to the Los Angeles Times, The Pirate Bay is "one of the world's largest facilitators of illegal downloading", and "the most visible member of a burgeoning international anti-copyright — or pro-piracy — movement."

Website setup

The Pirate Bay website allows users to search for and download BitTorrent files ("torrents"), small files that contain machine-readable information necessary to download the data files from other users. The torrents are organized into categories: Audio, Video, Applications, Games, Other, and Porn. Registration requires an email address and is free; registered users may upload their own torrents and comment on torrents. Downloading data files from other users is facilitated by the BitTorrent trackers that also run on The Pirate Bay servers. The website calls itself "the world's largest BitTorrent tracker" and is ranked as the 120th most popular website, according to Alexa Internet.

Initially, The Pirate Bay's four Linux servers ran a custom web server called Hypercube. On 1 June 2005, The Pirate Bay updated its website in an effort to reduce bandwidth usage, which was reported to be at 2,000 HTTP requests per second on each of the four web servers, as well as to create a more user friendly interface for the front-end of the website. The website now runs Lighttpd and PHP on its dynamic front ends, MySQL and MySQL-proxy on the two database back ends, Sphinx on the search system, Memcache for caching SQL queries and PHP-sessions, and Varnish in front of Lighttpd for caching static content. The Pirate Bay consists of 24 dedicated servers including six dynamic web fronts, two databases, and eight BitTorrent trackers.