Microsoft seems to be at the center of all the rumors right now in a way normally reserved for Apple. Aside form the mystery media event in Los Angeles later today, where Microsoft is expected to make a tablet-related announcement of some sort; it’s also the focus of speculation that it is finalizing talks to acquire Yammer for around $ 1 billion.

Yammer is a social network with a twist. It’s a private social network intended for business use. Yammer is like Facebook, but a Facebook that’s segregated from the rest of the Internet, and that provides monitoring and controls for IT admins to be able to enforce policies and protect information.