How Facebook is killing democracy – all the facts so far has a nice overview of the Facebook/Cambridge story so far. This story is full of links to the first-hand sources: How Facebook is killing democracy … :

A Cambridge Analytica executive explained: “There are two fundamental human drivers … hopes and fears … and many of those are unspoken and even unconscious. You didn’t know that was a fear until you saw something that evoked that reaction from you. Our job is … to understand those really deep-seated underlying fears, concerns. It’s no good fighting an election campaign on the facts because actually it’s all about emotion.”