"Twitter is not a triumph of technology," Biz Stone, the company's creative director, told an audience in San Francisco this week. "It's a triumph of humanity." As Stone describes it, Twitter is a tool for times of revolution and strife, a service that can break news, bring down tyrants, and salve the wounds of the forsaken. When Capt. Chesley Sullenberger landed his plane in the Hudson last year, Twitter was there. When activists in Iran took to the streets to protest a stolen election, Twitter was there. When earthquakes ravaged Haiti and Chile, Twitter was there. I spend many hours a day on Twitter, but even I was shocked to learn from Stone that I was changing the world in the process. I'd assumed it was mainly a way to find links to the terrible things Tea Partiers say about Obama. - Bonnie Foster