A Little Bit Torrent of Knowledge Can Go a Long Way
What is BitTorrent?BitTorrent is a peer-to-peer file sharing system designed for distributing large amounts of data. With the system, files are broken into tiny digestible chunks called torrents, and are pulled from multiple sources simultaneously. This results in two primary benefits: faster downloads; and lighter burdens for hosts. This also means that BitTorrent can't be shut down in one fell swoop, as was Napster, for instance.
Why do I need a "client"?When you download a torrent, all you're actually downloading is a file that contains information on how and where to find the file you want. To interpret this information, you'll need a client. There are tons out there, but we highly recommend uTorrent (Windows and OS X), Transmission (OS X and Linux), or Deluge (Linux, OS X, and Windows). Once you open a torrent, the client then communicates with one or more trackers to find users with all (seeders) or part (peers) of the desired file. These users make up what is known as the "swarm". Once you start downloading a file, portions of it are made available for others to download as they become available via your own computer. This makes you part of the swarm, and is how BitTorrent ensures that all participants share the burden of distributing data.
How do I find torrents?Finding torrents is simply a matter of searching a torrent indexer -- the perpetually troubled Pirate Bay being the most popular of such sites. The official BitTorrent page offers a search of multiple torrent sites, and there are also other very good indexers like BTJunkie, Demonoid, and ISOHunt. Note that these sites traffic illegally pirated films, music, and software. While we don't condone stealing, we want to be realistic, and if you're going to download pirated content, it's probably better to do so from reasonably trustworthy sources. Private torrent-tracking services add an additional layer of trust by filtering out dangerous or fake files. These members-only sites often specialize in specific content types (e.g. music on What.CD).
What can I download legally via BitTorrent?While BitTorrent is most popular for enabling the piracy of large files, such as films, there is also plenty of legal data passed around. LegalTorrents, Vuze, Public Domain Torrents, and Legit Torrents offer links to content (primarily B-movies and Linux distributions) that wont have the MPAA knocking on your door. There are also artists, like Trent Reznor, who freely share their music via BitTorrent, and many software companies use the protocol for large downloads, including those offered by Microsoft and Ubuntu.
Anything else?One last warning before you ditch LimeWire and embrace the world of torrents: there's a lot of malware out there. Internet ne'er-do-wells, record companies, and movie studios won't hesitate to flood the Web with fake torrents, and some of it is loaded with viruses and other malicious code. Before you download anything from a torrent site, legal or otherwise, make sure to read the comments. The torrent sharing community is very active and vocal; if users warn against downloading something, you should probably listen.
Now that you know all the buzz words, how it works, and how to stay safe, we wish you happy hunting. And, if the RIAA sues you for copyright infringement, we don't know you.