Facebook CEO Mark Zuckerberg waits for a joint hearing of the Senate Commerce, Science and Transportation Committee and Senate Judiciary Committee on Capitol Hill April 10, 2018 in Washington, DC. Zuckerberg, making his first formal appearance at a Congressional hearing, seeks to allay widespread fears ignited by the leaking of private data on tens of millions of users to British firm Cambridge Analytica working on Donald Trump's 2016 presidential campaign. / AFP PHOTO / Brendan Smialowski