The tragic death of Khaled Said—the 28-year-old who in June 2010 was dragged from an Internet cafe in Alexandria and beaten by the Egyptian police—was the event that galvanized young Egyptians, pushing them to share their grievances on Facebook. A group called "We Are All Khaled Said" quickly reached hundreds of thousands of members and played an instrumental role in promoting the protests that eventually swept Hosni Mubarak from power.

The Egyptian experience suggests that...