You read that right: Hong Kongers have found an app that allows users to communicate without using the Internet or mobile signals.
Specifically, the Firechat app utilizes Bluetooth technology to allow users to send and receive messages. Protestors favor this medium because of rampant censorship of the Internet as well as rumors that the Hong Kong government might shut down cellular networks across the territory. Because Bluetooth only works over short distances, the aptly-named Firechat spreads the messages like a wildfire would, with information jumping from user to user in a widening social media chain. Unsurprisingly, the app's forte is transmitting messages across large groups of clustered individuals. For more information about this kind of mesh networking, here is a primer on the subject.
Though Firechat had been employed in protests in Taiwan and Iran this year, its significance in Hong Kong's demonstrations is unprecedented. At last count, over 100,000 downloads were recorded in the city in just 22 hours, with over 30,000 people using the app at one time on Sunday.