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“Dark ads.” That is the catchall term researchers use to describe online political messages that keep people in the dark about why they were targeted with the ads, who paid for them or how much was spent.
Thousands of dark ads ran on Facebook around the 2016 presidential election in the United States and the British referendum on leaving the European Union. Some ads delivered divisive messages aimed at specific audiences. Some ads circulated misinformation — or told people not to vote.
But in recent months, in response to criticism from the public and lawmakers, Facebook, Google and Twitter have tried to
