Cambridge Analytica, a London-based political consultancy, illicitly harvested the Facebook data of up to 87 million people to build psychological profiles of voters. Exposed by whistleblower Christopher Wylie in 2018, the scandal triggered a global reckoning over data privacy and democracy.
The firm was the British arm of the SCL Group, led by the Eton-educated chief executive Alexander Nix and backed by the American billionaire Robert Mercer, with Donald Trump's strategist Steve Bannon as a key figure. Its raw material came from a personality quiz app called thisisyourdigitallife, built by Cambridge University researcher Aleksandr Kogan. Some 270,000 people took the quiz, but the app also vacuumed up the data of their Facebook friends, ultimately amassing tens of millions of profiles without those users' knowledge or consent.
Cambridge Analytica used the data to build psychographic models based on the OCEAN personality framework, measuring openness, conscientiousness, extraversion, agreeableness and neuroticism, and then micro-targeted voters with tailored political messaging. The firm worked for Senator Ted Cruz's 2016 presidential campaign and then for Donald Trump's campaign, and was linked, though the extent was disputed, to pro-Brexit campaigners in Britain's 2016 EU referendum.
The first warnings came early: Guardian journalist Harry Davies reported in December 2015 that the firm was using harvested Facebook data, and Carole Cadwalladr pursued the story for The Observer from 2017. But it was Wylie, a pink-haired former employee, who blew the scandal open in March 2018, telling The Guardian, The New York Times and Channel 4 News: 'We exploited Facebook to harvest millions of people's profiles.' The simultaneous publications on 17 March 2018 wiped more than $100 billion off Facebook's market value in days.
The fallout was historic. Mark Zuckerberg was hauled before the US Congress in April 2018, Britain's Information Commissioner's Office fined Facebook £500,000, the maximum then available, and in 2019 the US Federal Trade Commission imposed a record $5 billion penalty on the social network. Cambridge Analytica itself collapsed into administration in May 2018, and Nix was later disqualified as a company director.
The scandal became the defining parable of the data age, dramatised in the Netflix documentary The Great Hack and credited with accelerating Europe's General Data Protection Regulation. It also left an uncomfortable question hanging over British democracy: a London firm had helped pioneer the industrial-scale manipulation of voters, and nobody involved was ever criminally charged. Wylie himself later said he had helped build the tools of a system he came to despise, a confession that made him both hero and accomplice in the public imagination.