Facebook and Twitter, as the Republican candidate's platforms du jour, have come under some serious stick for allowing the spread of spurious stories and for polarising the political landscape. Dave McClure called Facebook a "propaganda medium".
So how is it possible that a company created to connect people is being blamed for dividing a nation?
62% of Americans get some or all of their daily news from social media. And a lot of this news is false or misleading.
On Sunday, Zuckerberg rejected the "crazy idea" that voters were influenced by bogus news stories, and countered with the assertion that 99% of what appears on Facebook is genuine.
According to Zuck, Facebook is not a media company; it's a neutral technology platform that feeds users the news and information shared by their friends. It learns from what we click on and therefore is more likely to show us stories that support our views rather than challenging us. This is what people mean when they call Facebook an echo-chamber.
With good old-fashioned newspapers, there are gatekeepers. Staff are employed to check facts and verify sources. However, as the media landscape changes, the priority of our news sources changes with it.
On Facebook, it's never about the story; the goal is revenue and engagement. Whether a story is accurate is less important than whether it is shared or liked. These engagement metrics are shifting the media landscape, meaning that clickbait, hyperbole and misinformation prevail.
Facebook's attempts to control the spread of fake news stories have largely failed. In January 2015, it launched a tool that allowed users to report fake news stories. This backfired because people tended to label any news report they didn't agree with as false.
Verifiable facts aren't the only issue here. Many stories contain no outright lies, but still twist the facts to reflect a highly partisan narrative. "The story is hijacked, along with the ad revenue" and no algorithm in the world can prevent this.
It seems unlikely that Facebook will be able to stem the flow of phoney news. Moreover, the company has little incentive to do so. To prevent users sharing stories goes against everything the platform represents.
Plus, clicks mean revenue – as long as we remain attracted to sensationalist articles regardless of veracity, Facebook will continue to provide us with what we want.