Firstly the main Messenger window that contains your contacts has changed somewhat. Included on the left hand side is a "social stream" of updates provided by Windows Live. These are updates from your Messenger contacts and the data is provided by Windows Live. In current public Messenger builds some of this integration is present at the top of a conversation window. Windows Live Messenger aims to add to this by using the "social stream" as a showcase for your contacts updates. Providing your friends have including their Facebook, Twitter and Blog posts into Windows Live then you will see this in the stream.