The Microsoft Research Social Computing Group Web site provides an interesting insight into possible future directions for MS products and services in this area:

"Our mission in the Social Computing Group is to research and develop software that contributes to compelling and effective social interactions, with a focus on user-centered design processes and rapid prototyping.

Our work includes the Sapphire project, sharing, mobile applications, trust and reputation, collaboration, and story telling. To facilitate the rapid prototyping, we also have an online lab for running studies to evaluate our social user interfaces. "

There has been a lot of discussion recently about Microsoft's experimental social networking tool Wallop, which seems to be built on top on Instant Messenger. Looking at this research group site, it is clear where some of the ideas and component parts of Wallop comes from.