Personal data of 50 million Facebook users was handed out to Cambridge Analytica, a political consulting firm in the UK, in breach of the terms governing the use of such data. The firm, hired by President Trump's campaign in 2016, is suspected of exploiting the data by launching behaviorally targeted political messages to prospective voters. 

The collection of personal data began in 2014 through an online Facebook app for personality tests called "thisisyourdigitallife". The app was developed by a researcher from Cambridge University and distributed as a tool that offers psychological prediction. It gained over one quarter of a million direct users, but also collected data about their Facebook friends and the ‘likes’ that those friends tagged, amounting to tens of millions of users. Although Facebook provided the option to block the app's access to user personal data, Facebook's default settings at that time granted such access.

The U.S. Federal Trade Commission (FTC) has launched an investigation regarding the privacy practices of Facebook, particularly in connection with the Cambridge Analytica affair. In parallel, The European Commission demanded that Facebook provide answers regarding the impact the data leak has had on European residents and whether the misuse of data could recur nowadays. A UK parliamentary committee on media has summoned Facebook’s CEO, Mark Zuckerberg, to testify. 

The Israeli Privacy Protection Authority also announced that it has opened an administrative investigation into whether Facebook unlawfully used personal information of Israeli users in violation of the Israeli Privacy Protection Law.