Online social networking as it is offered by services such as Facebook and MySpace is thought of as free since there is no charge to join, but each of these social networks is trapped in its own walled garden – a term coined to refer to closed sets of information services.

The keynote lecture, Open Source Imagined Networks, part of the POSOA event, CODE: Building the New Agora, is freely available for viewing with ePresence Interactive Media , an innovative Web-casting system created by the Knowledge Media Design Institute at the University of Toronto.