Most of us use BitTorrent to download Pirated Stuffs from the Internet. Some Download movies, Games, tv series and some download Softwares, OS, Nulled stuffs etc. Almost everything you download from torrent is Illegal.
But do you think that BitTorrent is used ONLY for Pirated Stuffs? If you are thinking like that then you are wrong. BitTorrent is a Client or a protocol which lots of People use in other way.