With a clear and simple tweet, Blizzard announced today that Hearthstone: Heroes of Warcraft, the free-to-play and pretty addictive digital card collecting and dueling game, has broken the barrier of the 20 million users already. The achievement comes just half a year after its PC and Mac debut, and not even five months from its well received iPad adaptation.
The post, and its accompanying celebration card, can be seen below:
Multiplying World of Warcraft's current userbase several times over, it's undoubtedly Blizzard's biggest game right now, and despite following a F2P model, it could also become the biggest earner for the company, though that's more difficult to estimate.