At the other end of the spectrum is private property. But Twitter isn’t a public forum, most obviously because it isn’t run by the government (even though its censorship is sometimes at official behest). Speech protection is strongest in a “public forum.” If Twitter were such a forum, almost all content blocking would be an impermissible prior restraint. The first step to solving these conundrums is to recognize that different free-speech principles apply in different contexts, and there are three key different kinds of forums.
