Valve has said it has tracked DotA 2 at over 3 million unique monthly players.
That colossal figure has been reached despite the game still being in beta form, with over 100 million matches having been played."With over 3 million unique players every month, the Dota 2 community is blossoming into a beautiful flower," said Valve.
The huge success of the DotA 2 beta wasaccredited with playing a significant role in helping Valve's Steam platform to hit a new milestone recently, when it logged over six million concurrent users.
Valve yesterday released the latest DotA 2 beta update which, among a list of changes, added a new 'Least Played' mode to matchmaking, which forces players to choose from a list of their least played heroes.

http://www.computerandvideogames.com...monthly-users/