Since the Cambridge Analytica Facebook data scandal, the number one question I've been asked is, "What Facebook data did they get?" The second most popular question is, "What did Cambridge Analytica do with it?" Let's review:
What we've been told
According to Mark Zuckerberg, "In 2013, a Cambridge University researcher named Aleksandr Kogan created a personality quiz app. It was installed by around 300,000 people who shared their data as well as some of their friends' data. Given the way our platform worked at the time this meant Kogan was able to access tens of millions of their friends' data." Later in the same post, Zuckerberg claims that the issue surfaced again in 2015 and Facebook took action (perhaps not enough action) to bring the offending company into compliance with Facebook policies.