I hate to have a cynical take on this, but. This acquisition has more to do with shoving a sharp stick into Google, than it does about propping up the Live offerings. The only people that I know that use Skype are expats, people with family that live abroad.
I'm not sure what kind of patents Skype holds. But I'm sure they, when placed in Brad Smth's hand, could be used to make Larry Page just a little more bat-SHlT crazy.