Messenger (instant messaging)

You can use Extensible Messaging and Presence Protocol (XMPP), an open standard for real-time communication, to enable your apps to interact with a Windows Live Messenger user and his or her buddies.

• Getting started using Messenger with XMPP
  Get a user's okay for your app to act on his or her behalf, and then sign in to the Messenger XMPP service.
• XMPP code examples
  Exchange instant messages and get a user's info and his or her buddies' info, including their friendly names, display tiles, presence info, and status messages. Also, update a user's status message for the duration of a session.
• Sharing a user's status
  Update a user's status message between sessions by using the Live Connect APIs.