While Dota 2 is widely accepted as the most played PC game thanks to Steam's stats page, it probably comes as no surprise that Minecraft is more popular. Mojang's Nathan Adams Tweeted last week that the company has gained access to concurrent player statistics, and the results are staggering: over 998,000 people were playing Minecraft when Adams Tweeted on January 9, and it wasn't even peak hour.
I could have waited 5 minutes to say 1 million, but nobody would believe that. :DJanuary 9, 2015
Keep in mind that this figure accounts for the Windows, Mac and Linux versions of the game. Minecraft is also available for most consoles and smart devices, while older and pirated versions of the game aren't included in the figure. That means there's probably a lot more than a million people playing Minecraft at any given moment. It makes Dota 2's Steam stats look fairly casual by comparison.