How a Trump campaign contractor learned how to read your mind

Cambridge Analytica, contracted by the Trump campaign, used psychographics to segment voters by personality, creating targeted ads that could influence voting behavior, with access to 270,000 personality tests and data from 50m Facebook users.
University of Cambridge academic Aleksandr Kogan provided Cambridge Analytica with the personality test data, which was used to build profiles for over 100m registered US voters, allowing for individually tailored ads designed to elicit specific responses.
Cambridge Analytica's approach to behavioral analytics and psychographic profiling has been criticized, but its legacy is likely to be the industrialization of personality-based marketing and electioneering, with the company developing dozens of ad variations on different political themes tailored to unique personality profiles.