Christiane C. didn’t think anything of it when her 10-year-old daughter and a friend uploaded a video of themselves playing in a backyard pool.

“The video is innocent, it’s not a big deal,” said Christiane, who lives in a Rio de Janeiro suburb.

A few days later, her daughter shared exciting news: The video had thousands of views. Before long, it had ticked up to 400,000 — a staggering number for a video of a child in a two-piece bathing suit with her friend.

“I saw the video again and I got scared by the number of views,” Christiane said.

She had reason to be.

YouTube’s automated recommendation system — which drives most of the platform’s billions of views by suggesting what users should watch next — had begun showing the video to users who watched other videos of prepubescent, partially clothed children, a team of researchers has found.

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Source: On YouTube’s Digital Playground, an Open Gate for Pedophiles – The New York Times