"During a two year beta, Dota 2 grew to be the largest active community on Steam ever, with a monthly user base over 3 million users, and peak concurrent users of over 300,000. The feedback from these users has put Dota 2 in position to welcome everyone to come play, as we move from beta to launch.
Today, the Dota 2 Beta is over and the game is now available. Given the size of the Dota audience, the initial launch of the game will be done in waves. You can find all the details on how to join the Dota 2 community
here."