In one of the deadliest mass shootings in American history, a gunman in a high-rise hotel in Las Vegas opened fire on a huge outdoor concert festival, sending thousands of terrified survivors fleeing for cover.
Users on 4chan had misidentified the shooter as a man named Geary Daniel, and that misidentification made the rounds on the internet, leading to false claims about the gunman and incorrect reports of his motivations.
The Gateway Pundit said the attacker was reportedly an anti-Trump Democrat, a lover of liberal TV host Rachel Maddow, and a "far-left loon". The site, which earned White House credentials under Trump, later deleted the story and apologised for the error.
However, 4chan users on /pol-a forum known for its distaste of politically correct culture often attributed to liberalism-quickly picked up on the interests of Geary Danley as indicated by his Facebook like, many of which identified him as a liberal.
The incident highlights yet again how news and social-media algorithms created to help surface the best information can fall short in the hours after a major incident, when few factual details are readily available because authorities have yet to confirm or release them. "Within hours, the 4chan story was algorithmically replaced by relevant results.This should not have appeared for any queries, and we'll continue to make algorithmic improvements to prevent this from happening in the future".More news: 'Saturday Night Live' hammers President Trump over Puerto Rico response
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Facebook has launched its Safety Check in the aftermath of the shooting. "However, their removal was delayed, allowing them to be screen captured and circulated online".
"We are working to fix the issue that allowed this to happen in the first place and deeply regret the confusion this caused".
Facebook said its security team removed Gateway Pundit results and other similar posts from its social network, some within minutes.
A Twitter spokeswoman said: "We are reviewing and removing content that violates our rules - both proactively and through reports".
Distributors of fake news used Google and Facebook's algorithms to their advantage to spread hoaxes in the midst of the Las Vegas massacre. Both tech companies are facing questions about possible roles they may have inadvertently played in Russia's campaign to influence the 2016 election.