Telepathy is a D-Bus API which abstracts the job of talking IM, VOIP and other real-time communication protocols, meaning applications can access these functions regardless of the underlying protocol, and connections can be shared between separate applications on the desktop.
Forthcoming versions of the specification will introduce the concept of "tubes", which will provide a means for applications to use the Telepathy backends to establish direct peer-to-peer connections to other Telepathy users. The connection manager will take care of the signalling over whatever protocol is in use, and any complexities like NAT traversal, and provide a channel for exchanging data between the users' applications.
This talk will provide a rationale for the Telepathy approach, an introduction to the basic concepts and a review of the current state of implementations. We will go on to look at how Telepathy is being used in the OLPC project, how it could be used in the GNOME desktop to integrate messaging and presence, and particularly how to make use of tubes to achieve new levels of collaboration and communication between desktop applications.