Not really, thanks to magnet links and the dht you don't even need trackers. Sure, you need the magnet link, but you could even distribute them in grafitti or monthly paper issues if you felt inclined.

Or using a decentralized network too: http://www.tribler.org/

Fantastic! Why have never heard of it before?

Sorry, a bit of an overstatement.

I was comparing it to Napster, and I thought Kazaa also had a central repository.

But both Kazaa and eMule have the same "supernode" like search mentality as bit-torrent (in bit-torrents it's the trackers).

I was referring more to the fact that unlike Kazaa/eMule where you needed to first find a "supernode" and then search for the file, bittorrent actually had the "tracker" url inside the download link (.torrent or magnet link).