Some of the most viral news stories during the presidential campaign were entirely untrue.
Tom Cheshire, Technology Correspondent
Remember when Pope Francis endorsed Donald Trump for president?
When Donald Trump said that female US soldiers should expect to be raped?
That Hillary Clinton was so unhealthy she might be replaced by a body double for the debates?
How Trump, in an interview for People in 1998, said: "If I were to run, I'd run as a Republican. They're the dumbest group of voters in the country"?
These were some of the most viral news stories during the presidential campaign. But they were entirely untrue.
They went up like a bonfire nonetheless, shared millions of times on Facebook.
These hyper-partisan posts - from both sides of the political spectrum - are poisoning civil discourse, playing to conspiracy theorists, making suckers of the public.
The EU referendum saw a similar phenomenon, even though some misinformation was also printed on buses.
Conspiracy theories and fake news predate social networks. But Facebook and Twitter supercharge them. A story from a "fantasy news website" (that Pope Francis endorsement) ends up in your newsfeed, its context removed, presented in the same format and in the same digital real estate as an article from The New York Times or Sky News.
This is something fundamentally built into the business model of Facebook, which rewards attention. One of the biggest sources of fake Facebook stories, as BuzzFeed reported, was a small town in Macedonia. They weren't hardcore Trump or Clinton supporters seeking to bolster their candidate. They were publishing b******t because, thanks to Facebook, there was money in it.
A majority of US adults - 62% of them - get their news on Facebook, according to the Pew Research Centre.
Facebook - and Twitter to a lesser extent simply because it has fewer users - have a massive responsibility. It's one that most news organisations take seriously, because they realise how important a free and accurate press is to the proper functioning of democracy.
Facebook doesn't. All it cares about is keeping people clicking. Over breakfast this week, I asked Facebook's chief technology officer, Mike Schroepfer, what Facebook was doing to fix the problem.
"The first principle is, this is a system designed to give people what they're interested in," he said.
There was "thought" about journalistic standards, about "trying to at least convey truthful facts about things and have an honest civil discourse on these things".
But thought is as far as it goes. "That's a challenging thing to implement in these algorithms and in these systems, so I'm not sure where we're going to go with that.
"I think again it all starts with trying to get people what they want."
That's fine when it comes to sorting your friends' baby photos and event invitations. It's not fine when it's a falsified story about two white men being set on fire by Black Live Matters supporters, with the inevitable addendum "Media CENSORED".
"This video will make you sick!", that Facebook post promised. It did. This whole thing does, especially Facebook's refusal to even acknowledge its complicity.
Mark Zuckerberg said in August: "We are a tech company, not a media company."
That's a deliberate and sneaky oversimplification. As the technology academic Zeynep Tufecki wrote on Twitter: "Facebook's algorithm is central to how news and information is consumed in the world today, and no historian will write about 2016 without it."
They won't judge it kindly: Facebook is fiddling while democracy burns.
- Source Sky news report
