The game to end all games

Jonathan Ross is a level-seven dwarf. His wife is green and rides a spectral tiger. Macaulay Culkin is a level-70 Paladin. While it may sound like they are members of a strange cult, the truth is they are avid World of Warcraft players. And they are not alone. Matt Stone and Trey Parker won an Emmy for their episode of South Park based on WoW, and Mr T and William Shatner regularly appear in TV ads for the game.

Last week, Vin Diesel, Jimmy Fallon and the actress Mila Kunis lined up to support the launch of Cataclysm, the new World of Warcraft expansion pack at a convention in Annaheim California with an atmosphere more like a rock concert than a promotional event. Why do so many celebrities play World of Warcraft? That's easy, according Tim Edwards, the editor of PC Gamer magazine. "Eleven million people subscribe to WoW and celebrities are people too," he says.

World of Warcraft is the most popular massively multiplayer online role-playing game, or MMORPG, of all time. Four years old, its audience has long since moved beyond what is sometimes known as the "black T-shirt brigade" of adolescent males with social problems and is headed directly for the mainstream. "It's changed the gaming audience. Pretty well everyone I know plays," says Edwards. "I know dads who travel a lot who do quests together with their kids when they are away, as a way of keeping in touch. Quite a few girls play. Someone in every office will play World of Warcraft."

And it looks like it is going to get bigger. A live-action film adaptation by the director of Superman, Sam Raimi, is on the way and to celebrate the game's upcoming fifth anniversary, World of Warcraft magazine will be launched. Blizzard, the company behind WoW, has also set its sights on China, where 1.5 million people play the game in cyber cafes. "I think the numbers playing WoW will go up dramatically in the next six months," says Edwards. "They are opening up servers in China. The potential for growth is massive."

In the face of it, WoW is yet another role-playing game that draws broadly from Tolkein-style fantasy literature. But what makes WoW different is the quality of the build, say enthusiasts. Everything works well: users can play for short bursts or many hours and there is very little downtime waiting for characters to rest. The action takes place on Azeroth, a planet populated by competing races. Players create a character who can make money and friends while undertaking a series of quests. Things can get very geeky. It is possible to use the phrase: "I got the Spectral Kris off of BK in H ToC last night and put a +63 spellpower chant on it." However, it is still accessible.

"It is easy to play and you'll have a friend playing it as well," says Edwards. "It's very sociable. Last night I was playing with 25 people." And it is absorbing. Because players must complete quests and kill enemies in order to "level up", the game has been accused of encouraging people to play for many hours at a time. "I recently noticed I'd spent 100 days in-game," admits James Shea, a programmer from Austin, Texas.

"I got obsessed with WoW for the past few days,"says Barbara Wing, a college student from Boston. "I played about 80 hours in nine days and couldn't handle any more." A report published by Sweden's Youth Care Foundation said World of Warcraft was the most dangerous game on the market and "the cocaine of the computer games world". Richard Graham, a psychiatrist at the Tavistock Clinic in London, believes that Blizzard should fund the treatment of addicts. In 2005, a South Korean couple were arrested after their four-month-old child died when they left the baby alone to play World of Warcraft at an internet cafe.

Graham has suggested a team of psychiatrists go into the game to reach players addicted to WoW. In China, the government has taken direct action, imposing penalties on players who spend more than three hours playing a game by reducing the abilities of their characters. So far, Blizzard has refused to be held responsible for the fiendishly compelling nature of its game, possibly because there is too much at stake. At a cost of around £8 a month to subscribe, it is the world's most commercially successful role-playing game. And that is a situation that doesn't look set to change. Twenty six thousand people showed up to the Blizzcon convention last week, each paying $150 (Dh465) a ticket, just to hear about new WoW products and hear the in-house band - Level 80 Elite Tauren Chieftan.

"World of Warcraft is on the cover of our magazine every six months" admits Edward. "It is usually our biggest-selling issue. It's the only computer game I play."