The tweet is just trying to commend Bun and Acti on the deal. Sony knows that Bun is a very talented group and they also know that the PS3 is arguably the most powerful video game console ever.
So you put the 2 together (PS3 and Bungie), even if it's multi-platform and we get U2/GOW3 graphics mixed with Halo game play and hype.
Seems like Sony have already seen what Bun and Acti are working on.