Another enormous crowd turned out in Tahrir Square today, celebrating Google executive Wael Ghonim, who says he created a crucial Facebook page last June. It was dedicated to a victim of police brutality, and encouraged Internet users to share their anger. Now it's credited with starting the protests we see today. But is the Internet necessarily an instrument of democracy? Can it also be used by authoritarian regimes to enforce the status quo? We hear more about its role in Egypt, and how it's used in Iran and China. How is it regulated in the US? Should the government have a "kill switch," just in case?