The correspondence (PDF), which starts in September 2015 and runs through February 2016, provides fresh insight into when Facebook employees became aware of potential problems with the way Cambridge Analytica and other outside companies were using data from the social network. In one early exchange, a Facebook employee calls Cambridge Analytica "a sketchy (to say the least) data modeling company." Three months later, The Guardian reported that Cambridge Analytica was supporting Ted Cruz's campaign using Facebook data from tens of millions of Facebook users through an online quiz. The consultancy later worked on Donald Trump's campaign.
"We suspect many of these companies are doing similar types of scraping, the largest and most aggressive on the conservative side being Cambridge Analytica, a sketchy (to say the least) data modeling company that has penetrated our market deeply," an email dated Sept. 22, 2015, reads. The email asks for help determining what Cambridge Analytica was actually doing.
In a post, Grewal said a Facebook engineer could find no evidence that Cambridge Analytica was data-scraping, a form of automated information collection of public data that he called "a serious but frequent problem across the internet."
Roughly two and a half years after the first concerns, Cambridge Analytica was reported to have a received information from roughly 87 million accounts that was harvested through an app called "thisisyourdigitallife" that ostensibly offered personality predictions. The app, developed by a Cambridge University lecturer named Aleksandr Kogan, asked for access to users' Facebook profiles, locations, what they liked on the service, and their friends' data. Cambridge Analytica reportedly tapped the information to build profiles of users and their friends, which were used for targeted political ads in the UK's Brexit referendum campaign, as well as by Trump's team during the 2016 US election.
Watch this: Facebook, Cambridge Analytica and your privacy (The 3:59, Ep. 442)