[RawAlex]

Jace, no matter the legality of the content you are moving via bittorrent, the protocol in and of itself is abusive of the ISP's network. Your computer is used as a node for the commercial (and non commercial) distribution of software and music. Much of your bandwidth in a day may be used to do so.

P2P programs (plus things like Skype and Joost) are entirely dependant on leeching free bandwidth from ISPs to operate. The ISPs have to keep buying more and more bandwidth to keep up with customer demand, but really that customer demand is as much to keep these programs in operation as they are for uses limited to the end user.

You may not entirely understand, but systems like skype can use a huge amount of your bandwidth even when you aren't actively talking on the skype phone. Other calls get routed through you system, and if bandwidth permits, you can often be turned into a mini-super node that handled parts of hundreds of calls.

If you are sharing legal files, then just set up a server, pay the bandwidth and share your files. You don't want to do that because it would cost too much, right? Well, guess what... your ISP is paying for it when you use P2P. If you can't afford to do it, why should they have to pay to support it?