In the 1960s, way before anybody had ever tweeted, Facebook Live-d or sent classified information to WikiLeaks, one man made a series of pronouncements about the changing media landscape. His name was Marshall McLuhan and you've probably heard his most quoted line: "The medium is the message".
This video is narrated by Alex Chow, one of the leaders of the 2014 Hong Kong Umbrella movement whose mass street occupation was mobilised and reported via social media.