Telepathy

Telepathy provides a powerful framework for interacting with the user's instant messaging contacts. With Telepathy, all accounts and connections are handled by a D-Bus session service that's deeply integrated into the GNOME desktop. Applications can tie into this service to communicate with contacts.

With the Telepathy Tubes API, you can even tunnel an arbitrary protocal over modern instant messaging protocols like Jabber to create interactive applications. Create multi-player games or collaborative editors that integrate with the desktop-wide instant messaging services.