The digital demo - “SOCIAL media are the worst menace to society,” said Recep Tayyip Erdogan, Turkey’s prime minister, on June 2nd. Such fears delight dissenters. Protesters’ placards in Brazil goad the authorities with slogans such as “We come from Facebook”.

Enthusiasts called protesters in Egypt, Iran, Moldova and Tunisia “Twitter revolutionaries”. That was premature: much of the social-media content supporting the pro-democracy cause came from supporters abroad. But protests in Turkey and Brazil, where digital media are especially popular, do show how technology can muster, manage and amplify demonstrations. Zeynep Tufekci of Princeton University interviewed scores of Turkish protesters. Most cited social media as a spur.

The digital demo