The Pirate Bay has reached yet another milestone. Today, they track more than 20 million unique peers for the first time since the site was launched. It is estimated that the Pirate Bay tracks more than half of all BitTorrent users at any given point in time.

By November 2007, The Pirate Bay was tracking around 6 million peers, up from ‘just’ 3 million the year before. The growth has been amazing, and it doesn’t seem that it is going to slow down anytime soon.

One of the reasons it was possible for the site to handle this record number of peers are the constant improvements on the software and hardware side. New servers are added regularly, budget permitting, and UDP trackers were added to all the torrents on the site, which are less resource consuming than TCP trackers.

Pirate Bay co founder Peter Sunde, who just returned from his trip to Malaysia, told TorrentFreak that they previously had a limit on the amount of peers they could track, but that this has increased with all the recent changes. “I wish we had lots and lots of money so we could just buy like 10 servers and another gigabit,” he mused.

At the current growth rate, The Pirate Bay may be tracking over 25 million peers by the end of the year. Peter himself is aiming for 24 million peers by Christmas eve. The Pirate Bay is not the only BitTorrent site that has been growing, other torrent sites isoHunt and Mininova are breaking visitor records every week.

The only downside to this news is, that The Pirate Bay is one of the few sites that operates a (public) tracker. With 50% of all BitTorrent users relying on a single tracker, things can get quite ugly when it goes down. The Pirate Bay encourages others to start their own tracker, using Opentracker for example. The more heads the Hydra has, the better.