The data analytics firm that worked with Donald Trump’s 2016 winning election team and the winning 2016 Brexit campaign harvested millions of Facebook profiles of US voters, in one of the tech giant’s biggest ever data breaches, and used them to build a powerful software program to predict and influence choices at the ballot box.
https://amp.theguardian.com/news/2018/mar/17/cambridge-analytica-facebook-influence-us-election