they can be used for anything... warez to a perfectly normal demo file. it was designed with bandwidth load balancing in mind so thats its specific purpose... distributed bandwidth, but what you use it for is up to the creator.
torrents have been low key for a long time, guessing maybe a year or 8 months or so at least.
.torrent refers to BitTorrent. Bit Torrent can be used to transport Movies, Music, Applications, etc.
Highly illegal content such as Windows Longhorn may be downloaded via this increasingly popular method, and should be stayed away from. Datacenters have strong copyright infringement policies.
A .torrent file contains two critical parts: An announcement URL and file hashes. The accouncement URL points you to a server that will tell you the addresses of other peers downloading the same file. The hashes give your bittorrent click information to check that what it's downloaded is proper and intact. It generates a hash on each part it downloads and compares it to the file, if they don't match it tries to download the part again.
Hosting the .torrent isn't really an issue. What is the issue is if the announce URL is pointing to your server. You can run a bittorrent server from standard webspace with something like bitgrog. If they're running a really popular torrent with lots of peers (we're talking several thousand), then you might start noticing some effect on your resources. Bandwidth isn't the issue, but processor speed is. Being a bittorrent server requires more horsepower than transfer speed right now. Chances are, if this is a small torrent seeding, it won't be any issue.
Bittorent's actually a highly useful method of content distrobution. The technology is being used for Valve's Steam distrobution of Half Life 2 and Blizzard's distrobution of World of Warcraft client updates. A number of download sites, such as 3dgamers, have picked up on the technology and offer torrent files alongside their normal direct downloads. It's a great technology because it increases the available bandwidth pool for content distrobution. I have a 1.5/768 DSL connection here, which means I can give back half of the bandwidth I take (at least). It essentially reduces bandwidth usage by 50% in my own case. If people leave their clients open longer, then the bandwidth benefit increases more because they are no longer taking, just returning bandwidth.
Former owner of A Small Orange New owner of <COMING SOON>