According to TorrentFreak, Blizzard Entertainment’s smash hit of the year, Starcraft II, has become the most pirated game of 2010.

On its release day alone, almost 100 000 copies were downloaded illegally over BitTorrent, one of the world’s largest file sharing sites, with the unauthorized copies appearing almost simultaneously with the official release.

According to TorrentFreak’s statistics there have been 260 000 illegal downloads of Starcraft II since its release, with 50 000 people actively sharing the game files.

It’s not all bad news for Activision Blizzard though, as BitTorrent is also assisting their sales. Users have the choice of purchasing a serial key to the game and can then download the game legally through Blizzard’s official BitTorrent downloader.

It is rare to see a file sharing site benefiting the content owners, but Blizzard’s BitTorrent distribution client makes this possible. Do note that both legal and illegal versions of the game can be found on BitTorrent, the legal versions requiring the purchase of a CD key.

If these download rates are anything to go by, it’s easy to see why Starcraft II is the best-selling PC game of the year. 

Though the legal download figures aren’t known at the moment, with such tremendous demand for the game there’s a good chance that it will claim the spot of biggest BitTorrent swarm ever.