Use BitTorrent to, cough, illegally download music, movies, games and whatnot? If you do, you might want to watch this video, which explains how tracking agencies (the companies the **AA hire to track your downloads, often leading to a letter from your ISP saying you’ve been caught) do what they do. It’s fairly informative and will tide you over until the MacWorld three ring circus begins in a couple of hours.
I do use PeerGuardian (well, SafePeer, to be exact) when I use Azureus, mainly for the illusion that I’m being protected. Who knows if it actually does anything.
Video: How People Are Tracked Using BitTorrent [TorrentFreak]