I recommend reading this interesting and important article about "the Deciders." That's the author, Jeffrey Rosen's, term for the people in charge of content policy at Google, Twitter, and Facebook, whose "positions give these young people more power over who gets heard around the globe than any politician or bureaucrat—more power, in fact, than any president or judge."
I strongly agree with this part:
"The company that has moved the furthest toward the American free-speech ideal is Twitter, which has explicitly concluded that it wants to be a platform for democracy rather than civility. Unlike Google and Facebook, it doesn’t ban hate speech at all; instead, it prohibits only “direct, specific threats of violence against others.” Last year, after the French government objected to the hash tag “#unbonjuif”—intended to inspire hateful riffs on the theme “a good Jew ...”—Twitter blocked a handful of the resulting tweets in France, but only because they violated French law. Within days, the bulk of the tweets carrying the hash tag had turned from anti-Semitic to denunciations of anti-Semitism, confirming that the Twittersphere is perfectly capable of dealing with hate speech on its own, without heavy-handed intervention.
As corporate rather than government actors, the Deciders aren’t formally bound by the First Amendment. But to protect the best qualities of the Internet, they need to summon the First Amendment principle that the only speech that can be banned is that which threatens to provoke imminent violence, an ideal articulated by Justice Louis Brandeis in 1927. It’s time, in other words, for some American free-speech imperialism if the Web is to remain open and free in twenty-first century."