File sharing is the practice of making files available for other users to download over the Internet and smaller networks. Usually file sharing follows the peer-to-peer (P2P) model, where the files are stored on and served by personal computers of the users. Most people who engage in file sharing are also downloading files that other users share. Sometimes these two activities are linked together. P2P file sharing is distinct from file trading in that downloading files from a P2P network does not require uploading, although some networks either provide incentives for uploading such as credits or force the sharing of files being currently downloaded.
(In My Word's)
File sharing is an open standard software running on an open protocol, free for the public to use. It allows you to share any file such as .mp3s, .avis, .jpgs, .tiffs, etc. It normally runs on Windows, Macintosh, and Linux, and other computing platforms. "Publish your original content to the world without setting up a website!" it what is claims to be put most of the files on the network are copyrighted!! The way I see it is it depends on how you use it! most people wont download from sharing sites are usually poor people and spammers! in conclusion "you get what you pay for" which can leave your computer with nasty viruses! if you are going to use it, then use it wisely!
Other companies like imesh and the new bearshare have a legal p2p system were when you download copyrighted material you don't "Own" the music but all non-copyrighted music is free