In The Wake Of Fake News, Don't Expect Facebook To Be A Media Watchdog

Election 2016 wound up with multiple fingers pointed at Facebook. Critics charged that the social media platform was indirectly responsible for Donald Trump’s election, by allowing fake news sites to distribute false information about Hillary Clinton in its News Feed unchecked.
Naturally, Facebook co-founder Mark Zuckerberg thinks that’s unfair. Last week, he told the Technomony conference that it was ludicrous to say that Facebook’s News Feed had unduly influenced the election.
“Personally I think the idea that fake news on Facebook, which is a very small amount of the content, influenced the election in any way — I think is a pretty crazy idea,” Zuckerberg said. “Voters make decisions based on their lived experience.”

And in a Facebook post on Saturday, Zuckerberg added, “Of all the content on Facebook, more than 99% of what people see is authentic. Only a very small amount is fake news and hoaxes.”
He said the company will roll out additional measures allowing Facebook users to flag hoaxes and deliberately misleading news. Then, Zuckerberg added a big caveat.
“I am confident we can find ways for our community to tell us what content is most meaningful, but I believe we must be extremely cautious about becoming arbiters of truth ourselves.”

Forbes