Dota 2 broke the 1 million mark for concurrent users this past weekend. That means that there were over 1 million people actively playing the game according to Steam. This is the first game to break the 1 million concurrent user mark on Valve’s Steam client.
This number still does not compare to the numbers that League of Legends puts up at anywhere from 5 to 7.5 million concurrent users. Still this is very significant milestone for Steam and it is more than double the second most popular game on steam (Counter-Strike: Global Offensive), which has some 420,000 concurrent users.
Source: Polygon | News Archive