Facebook CEO Mark Zuckerberg (L, Front) arrives to testify at a joint hearing of the Senate Judiciary and Commerce committees on Capitol Hill in Washington D.C., United States, on April 10, 2018. Facebook CEO Mark Zuckerberg told Congress in written testimony on Monday that he is "responsible for" not preventing the social media platform from being used for harm, including fake news, foreign interference in elections and hate speech. (Xinhua/Ting Shen)