Now the Internet has eliminated the barriers of geography, cost, and time. All those blogs and social networking sites are helping existing tribes get bigger. But more important, they're enabling countless new tribes to be born—groups of ten or ten thousand or ten million who care about their iPhones, or a political campaign, or a new way to fight global warming. And so the key question: Who is going to lead us?
The Web can do amazing things, but it can't provide leadership. That still has to come from individuals—people just like you who have passion about something. The explosion in tribes means that anyone who wants to make a difference now has the tools at her fingertips.