Far more than 87 million people may have had their Facebook data harvested by Cambridge Analytica, according to evidence from former employee Brittany Kaiser.

Speaking to the Commons digital, culture, media and sport select committee, Kaiser said Cambridge Analytica had a suite of personality quizzes designed to extract personal data from the social network, of which Aleksandr Kogan’s This Is Your Digital Life app was just one example.
https://www.theguardian.com/uk-news/2018/apr/17/facebook-users-data-compromised-far-more-than-87m-mps-told-cambridge-analytica