It's not an "exploit". This stuff was freely given to Obama back in 2012. My best friend was a canvasser and before going into each house, the iPad they used told canvassers what to talk about and not to talk about. It knew who was pro-life so you wouldn't bring up abortion. It knows who's pregnant and who's recently had an abortion (you can get this through knowing what purchases someone has made and not made). There is a file on everybody, their intricate political and consumer dispositions, and this is Facebook's product. CA has blown up in the news despite being only one of many consumers of the same thing because journalists can make the technically true charge that they are "Trump’s election consultants" and millions are primed to go apeshit at that. But CA is just one of many buying the unethical products, and Facebook is just one of many producers of these data sets.