BitTorrent was created by Bram Cohen as a way to distribute large files around a network. There is a lot of potential behind BitTorrent, especially for people who need to distribute large files to Internet users. If you had a 1GB file and there was 300 people trying to download it, it would take a lot of time to distribute 300GB of data for most people. So instead, you distribute the file in small pieces to users who then share them around with other users until they have the full file. After they have the full file they can continue to upload to other users to help them also get the full file, this is known as seeding, and we will see it later. A large commercial site could also use BitTorrent to spread updates for their software to cut back on bandwidth costs. The speed of BitTorrent can be absolutely amazing, with very large files transferring in a few hours. Several sites have been setup to distribute pirated content across the Internet and as usual, groups such as the MPAA are quick to blame the technology and not those who use it for piracy. However, BitTorrent is not an evil creation by a rampant pirate, it was a development by Bram to help distribute content quicker around an unreliable network. Its use should be embraced by websites all over the world and Bram should be praised for it.
BitTorrent is not like P2P networks such as eD2K or FastTrack, you cannot make a search for files using a BitTorrent client. Instead you go to websites that list Torrent files. These torrent files, have information on the files you want to download and also information on the tracker you must connect to to begin downloading and sharing those files. The tracker is like the central server, that keeps information on each user currently currently sharing the files, and what part of the files they have. Once you download a Torrent files, your BitTorrent client (eg. Bit Torrent, Bit Tornado, Azureus etc.) should launch immediately and connect to the tracker. The tracker then connects you to Seeds and Peers who are sharing the file and your download should start. Once you have at least one bit of the file, you will start uploading that bit to other users who don't yet have it. So there we see how BitTorrent is different from other P2P networks, all it needs is the torrent file for the files (or folders) that you wish to download and share and then it does the sharing work for you.
Sites that list torrent files (like suprnova.org) have their trackers to handle the downloading and sharing that the users are doing. A torrent file would have the details on the tracker so you can only use a torrent file on the tracker it was made for. Software exists for anybody to setup their own trackers and build their own torrent files.
These three terms are very important. They all represent users who are currently using BitTorrent to share files or folders. A Seed is a user who has 100% of the file or folder and is currently still uploading the file to other users. Peers would not have 100% of the file but are currently downloading more parts and uploading the parts they have to other peers. Leechers is a term often thrown around and depending on what you are using, it has many different meanings. You could say that somebody who doesn't have 100% of a file is currently leeching the file but the correct meaning would be somebody who is downloading the file, but has either cracked their upload or limited it so much they are barely uploading at all. These users are called leechers because they just grab their files and go. They slow down the overall file transfers. As I have said however, the term is thrown around, so if you are on a website that says there is currently 1000 leechers using a torrent, don't immediately think it means people who aren't uploading and are just taking from everybody without participating at all. For sharing through BitTorrent to work successfully, there has to be at least one active seed still using a torrent.
There are many sites that list torrent files. To use these sites, all you would have to do is click on a file listed, and it should download automatically and your client should immediately connect to the tracker and start the downloading. Some known sites that list torrent files are...
Suprnova.org - (Only works with original BT client)
FileList.org - (Requires registration and read FAQ)
AfterDawn is not affiliated with any of these sites, I have just gotten these four links from the filesharing forums. You can visit AfterDawn's Forums to see if you can find more torrent site links that members have discussed.
I had to write a small bit about uploading. Uploading on BitTorrent is vital. If you connect to a torrent that has just 3 seeds and 800 peers, then most of the sharing will be done between peers. If you download the whole file and have uploaded just 10% of that file and then leave, you are hurting the performance of that torrent. This kind of usage is very bad because if a lot of people begun doing it, then there would be very little seeds and eventually the seeds could disappear and there may be nobody left with 100% of the file. The full file still may be available as files are traded in small pieces, but if all users stopped uploading as much as they downloaded, torrents life wouldn't last long and when it was fully working, it would be very slow. Always make sure you upload as much as you download if not more. Someone who download 700MB and uploads 700MB still in the eyes of BitTorrent is not sharing properly. For the life of a torrent to go on for a long time at high speeds, all users should make sure they upload at least 150% of what they downloaded. When your torrents are done downloading keep them active until you reach this amount, or if you need to use the files, you can stop the torrent activity, use them (but do not alter them) and then click the same torrent again and you would be added to the tracker as a seed and would continue uploading again. Trackers has begun banning leechers, or keeping records of leechers as a way to deter their behavior, if you like BitTorrent, don't try and cheat it.
Written by: James Delahunty