From EA, Crysis 2 has been pulled from Steam (just checked myself) and is now possibly getting pulled from D2D and such so it's exclusive. The most annoying part, The Old Republic is apparently going to be Origin exclusive, so no Steam deals or anything on it.
Also strong possibilities Battlefield 3 will be exclusive to it, which will suck. I've bought too many games on Steam to start using more than one digital download service.
I'm not sure, at a guess I'd say it's probably yet another useless alternative, like Gamersgate or D2D, where you just download a small file, which then leads you on to download the full game.
Pointless, really. Given a choice I can't see many gamers using any of these other services over Steam.