The trackers contain pointers to the file(s) and/or their pieces. If you download Ubuntu via torrent, you're downloading from other people who are sharing the same file. The tracker points you in the right direction and logs your IP for the MPAA
Humans are the only creatures that won't live up to the their potential. Give everything your all. When you die, die on E.
So I ask you, what do you intend to do now?