It isn’t set in stone yet, but according to Eric Johnson of Valve cross platform is a goal for the PS3 version of
Portal 2. The hope of the team, according to an interview with
Made2Game is that the can make the PS3 version of Steamworks compatible with the PC/Mac versions of Steam.
The feature was confirmed later by Valve’s Mike Dunkle who stated “the plan is you will be able to play between the console and PC.” The cross platform feature will allow gamers to play cooperatively and potentially competitively on the PS3 version. There was no mention as to whether this feature would be considered for the Xbox 360 version. Perhaps Gabe Newell was dead serious when he said that the PlayStation 3 version of
Portal 2 would be the definitive console edition.
