MOLLY WOOD:

Cambridge Analytica, it's the U.S. offshoot of a U.K. company that was trying to do this sort of election based data gathering and analysis and they would consult with various campaigns to offer advice on how best to reach particularly undecided voters. You know, in order to pull this off they needed a lot of data quickly and it can be very expensive and difficult to get that information. So they, like so many other data brokers, turned to Facebook around 2014 and got a lot of users to install an app that was a quiz app. So you know this is actually pretty common behavior on Facebook. You'll see some kind of a quiz your friends are sharing it. It pops up in your News Feed and in order to take it you have to install a little app and it pops up a screen that says you know this app will gather your public profile information and your list of friends and it sounds pretty innocuous. Cambridge Analytica went to Facebook and said we're conducting academic research with this app. Facebook apparently said O.K. and didn't do a lot of diligence and through that, because they were able to get sort of the direct access from the people who installed the quiz app and then gather all the information from the friends of the people that had installed the app and that includes likes, you know their various posts, the pages that they subscribe to, just a ton of information. They were able to gather really detailed profile information on 50 million Americans.