One of the most popular online free-to-play PC games - Dota 2 - has reached the 6.5 million active monthly user mark.
Valve's multiplayer online battle arena (MOBA) game has also scrapped its queue system which provided players with gated entry into the game, meaning it is now live to all.
Its biggest rival, Riot Games' League of Legends, had some 32 million monthly active players as of late 2012, making Dota 2's userbase around one fifth of League's (if the 32m figure is still the case today).
"For the past several months, access to Dota 2 has been granted through a queue system that gated entry into the community," said Valve in a statement. "We’ve used this system to gradually increase the size of our playerbase, as we ramped up our infrastructure and improved the experience for new players.
"As we have recently completed a set of server management upgrades as well as released a huge number of enhancements to the new user experience, we’re going to remove all restrictions to playing Dota 2.
"Signups are no longer required to access the game, and we encourage everyone to join the 6.5 million active monthly users currently playing Dota 2."
Valve is also encouraging Dota 2 fans to recruit friends to play in order to acquire extra in-game bonuses.