A group of Facebook engineers identified a “massive ranking failure” that exposed as much as half of all News Feed views to “integrity risks” over the past six months, according to an internal report on the incident obtained by The Verge.
The engineers first noticed the issue last October, when a sudden surge of misinformation began flowing through the News Feed, notes the report, which was shared inside the company last week. Instead of suppressing dubious posts reviewed by the company’s network of outside fact-checkers, the News Feed was instead giving the posts distribution, spiking views by as much as 30 percent globally. Unable to find the root cause, the engineers watched the surge subside a few weeks later and then flare up repeatedly until the ranking issue was fixed on March 11th.
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Source: Facebook News Feed bug mistakenly elevates misinformation, Russian state media | The Verge