According to a tweet from Blizzard, its free-to-play strategy card game Hearthstone has now topped 20 million players worldwide. That's a pretty decent audience.
With Curse of Naxxramas already out and the developers further expansions (adding rafts of new cards) are in the works, it's unlikely to fade in popularity any time soon.
Despite the occasional bit of wonky card balance, Hearthstone's success is largely well deserved. It's worryingly addictive. The game hit the 10 million user mark back in March, after coming out of a lengthy open Beta process. Blizzard will be hoping to add a bunch more to that figure when the game launches on Android and iOS devices later this year.
The Hearthstone will be held at Blizzcon 2014 this November, with a prize pot of $100,000.