Yeah. They ran a social media influencing campaign based data aggregated from approx 270 million people. It’s debated on the degree of influence this data had.

One thing is certain though. Around 800 000 people had surrendered their data (admittedly through a seemingly benign Facebook app) to an app posing as just one of your usual fun personality quizzes. This data opened the floodgates through association to about 269 million other people due to the way FB APIs were set up.

This data was then used to create psych profiles that got utilized for targeted advertising.

Two of the biggest campaigns that used this data were Trump 2016 and the Brexit referendum.