Political data firm Cambridge Analytica obtained the data of 50 million Facebook users, constructed 30 million personality profiles, and sold the data to US politicians seeking election to influence voters, without the users’ consent. Although this was revealed in 2015, in March 2018 a former employee of the firm came forward with more details, placing Facebook's practices under intense scrutiny, and raising questions as to the responsibility of the Internet industry. The facts, wide-reaching implications, and open questions are explained below.