Shirky is a great thinker about what makes the social aspects of technology tick. His current theory goes something like this: There is a cognitive surplus brought about the increasing amount of leisure time in modern industrialized societies. For a generation, that surplus has been dissipated through the artifice of television. Now, that surplus is being put to use. Open source software, tagging, Wikipedia, and other social web phenomena are the early results.
The question now is, what happens when someone figures out how to move this phenomena out to the physical world. Someone posted this quote in the comments section to the podcast:
The effect of a newspaper is not only to suggest the same purpose to a great number of persons, but to furnish means for executing in common the designs which they may have singly conceived.
-Alexis de Tocqueville