Nine days after Facebook chief executive Mark Zuckerberg dismissed as “crazy” the idea that fake news on his company’s social network played a key role in the U.S. election, President Barack Obama pulled the youthful tech billionaire aside and delivered what he hoped would be a wake-up call.

For months leading up to the vote, Obama and his top aides quietly agonized over how to respond to Russia’s brazen intervention on behalf of the Donald Trump campaign without making matters worse. Weeks after Trump’s surprise victory, some of Obama’s aides looked back with regret and wished they had done more.
https://www.washingtonpost.com/business/economy/obama-tried-to-give-zuckerberg-a-wake-up-call-over-fake-news-on-facebook/2017/09/24/15d19b12-ddac-4ad5-ac6e-ef909e1c1284_story.html