Most recently , a rumor about the possible expansion of the Steam platform. It seems Valve seriously intend to port Steam on Mac. This would be great news for users of this platform. Valve posted a few pictures online that hinted at this fact: Rock, Paper, Shotgun , Eurogamer , MacRumors , MacNN and MacWorld . In addition, in the new Steam client update, you can find files for Macs, which also speaks in favor of a quick exit port.
Looks like porting Valve will announce at the Game Developers Conference in San Diego from March 9th to 13th of this year.