Another interesting feature of the Outlook Social Connector (OSC) is that it gives developers the ability to add new social network providers. "Developing a provider for the Outlook Social Connector" over at the Microsoft Office Outlook Team Blog has the details. Apparently the provider can be written in anything that creates a COM-visible DLL. The only contract is that it must return XML to the OSC that conforms to its XML schema.
I haven't even seen this tool yet, and they're already getting me excited about it. This seems like it's going to be great for people who already have Outlook as a pivotal component in their work environment.