There's now over eight million World of Warcraft players in the world, Blizzard Entertainent has confirmed — that's more than the population of Ireland.

Population highlights include over two million players in North America, 1.5 million players in Europe, and more than 3.5 million players in China.
Mike Morhaime, president and cofounder of Blizzard Entertainment said: “This milestone wouldn’t have been possible for us to achieve without the incredible support of our players. With the release of our expansion pack, World of Warcraft: The Burning Crusade, coming next week, we’re looking forward to welcoming more players to Azeroth and offering even more quality content for our community to enjoy.”
Since debuting in North America on November 23, 2004, World of Warcraft has become the most popular online multiplayer game in the world. It's available in seven different languages and is played in North America, Europe, mainland China, Korea, Australia, New Zealand, Singapore, and the regions of Taiwan, Hong Kong, and Macau.
World of Warcraft: The Burning Crusade, which will be available in North America and Europe on January 16, 2007.