Traditionally when a cross-platform game is released we must choose one version over the others to purchase. If you decide that you want both the PC and Microsoft Xbox 360 versions of, say, Assassin's Creed II, then you must buy the game twice. When it comes to Valve's big entrance on the Sony PlayStation 3 with Portal 2, however, the company is really going above and beyond to give players an incentive to buy the PS3 version of the game. As it turns out, every purchase of Portal 2 for the PS3 entitles the buyer to a free PC and/or Mac download of the game. Kotaku has the details.
All players have to do once they get the game is link their PlayStation Network and Steam accounts. Once that's done, they'll have a Steam Play (so, PC and/or Mac) version of the game ready to download in their library list.
This cross-platform play even extends to giving PS3 users the ability to chat to PC gamers, and vice-versa. Oh, and PS3 users can even save their game in the Steam Cloud, meaning Valve has them tucked away in their servers in case something ever goes horribly wrong with your PS3.
Thank you, Valve, for solving a problem with which I've been grappling. I prefer to play games on my PS3 so I can take advantage of my nice HDTV and superior performance of the console compared to trying to coax modern games to run on my aging PC, but I've been concered as to how I'll play this game with a controller as opposed to a keyboard and mouse (which I used to complete the original Portal on my PC in a rare subversion of the process). Now this is no longer an issue. I can get the PS3 version and bounce back and forth between platforms as I please. Other developers and publishers would do well to follow this example where applicable.