Shortly after the studio announced the game last August, it said that players on PC, Mac and PS3 would be able to face off against each other in multiplayer matches. Speaking to Joystiq, however, writer Chet Faliszek said the plan had been ditched due to lessons learned from the game's beta test.
"The beta has proved [that] we wanted to update not just the beta, but the game itself post-launch frequently on the PC," he said. "To do that we need to separate the platforms so one doesn't hamstring the other.
"So for that, we have removed the idea of cross-platform play – essentially make all platforms stronger by not mixing them."
In November, the company admitted that it was delaying the release of the Counter-Strike: Global Offensive beta due to feedback from professional players who had been helping test the game. The beta is ongoing, and you can sign up for it here.