Released in November 2004, World of Warcraft has since spawned the massively successful Burning Crusade expansion pack, with another, titled Wrath of the Lich King, on the way. The company regularly updates the game with new technology and gameplay tweaks via regular patches, the latest of which was released today.

Formerly a subsidiary of Vivendi Games, Blizzard was a major factor in the merger of Vivendi Games and Activision, with the resulting entity known as Activision Blizzard. At the time, Blizzard CEO and co-founder Mike Morhaime (pictured above) noted his belief that Vivendi shareholders never gave the studio "proper credit" and mentioned plans to increase subscriber numbers in other markets, such as Russia, Eastern Europe and India.

The studio is also known to be working on an unannounced MMO in addition to the long-awaited StarCraft 2.

"It's very gratifying to see gamers around the world continuing to show such enthusiasm and support for World of Warcraft," Morhaime said of today's milestone. "We're always pleased to welcome new players to the game, and we're looking forward to sharing the next major content update with the entire community in the months ahead."