What was long rumored is now true. Here's the word:

Valve announced today it will bring Steam, Valve's gaming service, and Source, Valve's gaming engine, to the Mac.

Steam and Valve's library of games including Left 4 Dead 2, Team Fortress 2, Counter-Strike, Portal, and the Half-Life series will be available in April.

So... Given that PC gaming is pretty much dead, this is curious timing. It's not like the Mac is a vibrant games platform. Though certainly adding Valve games to the system is a big deal and goes a ways towards changing that. My guess is that they'll make money. But I can't imagine this is going to ever challenge PC gaming let alone major game platforms like the video game consoles, iPhone, or portable video game systems (DS/PSP). Heck, even Facebook is a major games platform.

"Our Steam partners, who are delivering over a thousand games to 25 million Steam clients, are very excited about adding support for the Mac," said Jason Holtman, Director of Business Development at Valve. "Steamworks for the Mac supports all of the Steamworks APIs, and we have added a new feature, called Steam Play, which allows customers who purchase the product for the Mac or Windows to play on the other platform free of charge. For example, Steam Play, in combination with the Steam Cloud, allows a gamer playing on their work PC to go home and pick up playing the same game at the same point on their home Mac. We expect most developers and publishers to take advantage of Steam Play."

Pfft. See my previous comments about Microsoft trying this as well.

I don't know, this is a weird move in a way. But then it's really the only way Valve can expand. The iPhone and Xbox 360 (and dedicated game portables) are much bigger deals, but they're locked up by their owners already.