Valve says that their approach to cross-platform play is a lot like Sony's. Portal writer Chet Faliszek says that they don't think 'platform,' and that they're glad that Sony thinks along the same lines.
Faliszek goes on to say that Sony have been "really helpful" in setting up cross-platform Portal 2 and Counter-Strike: Global Offensive play between PS3 and PC.
He told Edge: "With Sony - and we've done it with Portal 2 - they've been great to work with on that stuff; they're really open to that idea. They think of it kind of like we do: we're gamers, we don't think 'platform'.
"Like, I own all the platforms, and I'll play games on whatever. I just want to play. And they've been really helpful that way."
If you're wondering how cross-platform play will work on the upcoming Counter-Strike: Global Offensive, Faliszek lays it out for Edge: "Xbox has its own community, but PS3, PC and Mac will all be able to play together."
I like to see them playing nice together, don't you?