BitTorrent is different to any other P2P file sharing network in a number of ways. The technology and the way you share the files is different, but the people who use BitTorrent are also part of a community, which you certainly don't get with things like soulseek and kazaa. In order to use BitTorrent successfully you need to understand it's background.
So lets start at the beginning. The single biggest difference between BitTorrent and other P2P networks is the fact that you MUST upload AT LEAST as much as you download.
Why though? Why can't you just download a file? As I explained in my beginners guide, when you are downloading a file you are actually downloading pieces of it from different people. You don't download the whole file from one person. Once you have downloaded a file you need to carry on uploading (known as seeding) yourself, so others can download pieces from you. This keeps the torrent 'alive'.
You wouldn't have the file in the first place yourself if others weren't uploading it for you and as a rule, the more people there are uploading one particular file the faster the download is for other people. So if you don't upload after your download you are slowing down and possibly also killing the download for other people. You are also making everyone else upload more, and if they are stuck uploading one file they cannot start uploading others.
If you do "Hit and Run" or "leech" a file you can expect to encounter problems severe enough to stop you from downloading other files. When you are in a "swarm" of a torrent (either uploading or download a file) your IP address is visible to others. Experienced users of torrents do not want to waste bandwidth uploading to people that just hit and run, so they keep an eye on the swarm and make a note of users who disappear once they have 100% completed - most torrent clients make this easy to do. They can then import your IP address into a blocklist and stop you from connecting to them ever again, meaning no more sharing.
The trackers of BitTorrent have one sole purpose too. They keep a record of the pieces of any file you have uploaded and/or downloaded. They automatically track your download to upload ratio. This ratio is sometimes publicly available, so any less than 1:1 will not make you very popular. In most cases it will get you banned from that tracker.
But I shouldn't need to tell you that, because the simple fact remains that without you uploading there is less of the torrent available for everyone. That includes you. You want fast downloads right? You want to have access to unlimited amounts of resources? Then you have to follow the rules, just like everyone else.
