The ps3 will get dedicated servers for any game using steamworks ^^, so we'll see how that progresses on that platform (I predict well).
Also activision are a HORRIBLE COMPANY, beyond belief. They are AGAINST new IP's ('we will take no risks, ever' -kotick), if crytek were under AV we would have never seen crysis and would be on far cry 28. Activison are the epitome of all that is wrong in gaming at the moment. They should collapse and all the developers move over to others (even EA is far better). They are just as bad as the company they spawned from.
I'm interested to see how it'll pan out anyway, since steam is a very powerful tool

Valve have created a platform as big as the consoles without needing specific hardware, and i've no doubt they're not particularly best buddies with microsoft at the moment after they refused steamworks on 360 because of the free updates and DLC.
Also, kinect is coming to PC soon

P.S. It's no so much as an attack on the xbox as a warning of the future if M$ don't react to what's happening on other platforms. Still, the 360's time is nearly up, as M$ will kill it stone dead when the xbox 3 comes out anyway, just like the original. So it won't matter much anyway!