Hearthstone, it turns out, is a pretty big deal. Activision and Blizzard are making tons of gol–ahem, money on this digital card game. How much, exactly?

Research firm SuperData has it that Hearthstone: Heroes of Warcraft makes $20 million a month. It draws in 8 million PC players each month and more than 9 million mobile players.

It’s making more money than Dota 2, according to Venture Beat.

So, yeah, all those packs and expansions? They’re working.

What’s really brilliant about Hearthstone is that, at least in my case, it’s totally possible to enjoy the game without ever spending a penny. Sure, that option is there for users who get tons and tons of mileage out of the software, but I’m totally cool with treating it as a free once-in-a-while card game.

Not everyone is doing that, obviously. Have you spent scratch on Hearthstone?