Carole Cadwalladr: Facebook's role in Brexit -- and the threat to democracy

In an unmissable talk, journalist Carole Cadwalladr digs into one of the most perplexing events in recent times: the UK's super-close 2016 vote to leave the European Union. Tracking the result to a barrage of misleading Facebook ads targeted at vulnerable Brexit swing voters -- and linking the same players and tactics to the 2016 US presidential election -- Cadwalladr calls out the "gods of Silicon Valley" for being on the wrong side of history and asks: Are free and fair elections a thing of the past?