Facebook/Cambridge Analytica (2018)

The Facebook/Cambridge Analytica scandal exposed how 87 million users’ data was harvested without consent for political advertising—three times more affected than the 30 million initially reported in the Equifax breach, and impacting 13% of Facebook’s 2018 user base. This incident outranks #6 LinkedIn’s 2021 scrape in direct policy failure, as Facebook’s own API allowed the data leak, whereas LinkedIn merely aggregated public profiles. The data leveraged psychological profiles for 50 million US voters, triggering a global regulatory shift that cost Facebook $5 billion in FTC fines alone.