One of the least important things the uprising in Tunisia is going to do is add more empirical fuel to the long-running debate about the role played by digital social media in fostering political and social change. In the grand scheme of things, what could be less important than the way a real-world revolution proves or disproves the theses put forward about the Internet by a subset of very smart public intellectuals? Nevertheless: expect the "what does Tunisia mean for the future of social media" debate to rage for the next few days on an RSS or Twitter feed near you.
Of course, we aren't lacking in deeply thought positions on this topic. Clay Shirky has written eloquently on these questions in the pages of Foreign Affairs, Evgeny Morozov has positioned himself well as a sort of "anti-Shirky," and Malcolm Gladwell has stirred the pot in the manner that only Malcolm Gladwell can do. I look forward to hearing more from all them in the coming days.
When the debate does pick up again, though, I wouldn't mind seeing a few new wrinkles added into the mix. What all of the above writers share, I would argue, is, first, a notion of collective action overly-indebted to definitions of action and coordination provided by economics, and (second) a somewhat a-historical focus in digital technology. One of the problems with the debate as it is currently structured is that other academic disciplines, particularly sociology, have largely stopped asking questions about the relationship between the media and social movements. Indeed, sociology has largely stopped asking questions about the media at all. (I'm generalizing wildly here, of course, but as evidence I would point you toward the cogently argued and well-titled article by Jefferson Pooley and Elihu Katz, "Why American Sociology Abandoned Mass Communication Research.") A second problem with the current debate lies in the fact that more complex theorizing about the nature of technological artifacts has yet to penetrate the mainstream debates over the roles played by technology in political protest.