The growth of sites like Twitter and Facebook has given rise to the idea that events have both a frontchannel (the Super Bowl, for example) and a backchannel (the live, online discussion from fans watching the game.) The next generation of Web-connected TVs and software will include ways for people to monitor and interact with the conversation happening around an event, filtering live streams in real-time to display the most relevant discussions.
It works on a smaller scale. The best example of the power of the backchannel at SXSW was an inadvertent one. An interview with Twitter founder Evan Williams was wrecked by criticism on Twitter. Festival goers were unimpressed with the questions posed to Williams by moderator Umair Haque of the Harvard Business Review and tweeted their displeasure before leaving the interview en masse. In a blog post later, Haque said he wished he had been monitoring the Twitter conversation from on stage.