According to research done by market analyst firm EEDAR
, Dota 2 is now installed on over 42 million Steam accounts. Recent numbers
released by Valve state that there are around 125 million active Steam users in the world, which would suggest that over a third of them play Dota 2. Earlier this month the game broke concurrent player records
during this year's New Bloom event, peaking at 1.26 million.
Dota 2 users aren't just numerous, they're also regularly active: more than 8 million player have spent over 140 into the game, suggesting that even though the game has a low entry barrier, being free to play, it has a large, dedicated core player base that is willing to invest a lot of their time in the game.