> but if you just post about how a lot of people are saying so-and-so has a child sex dungeon and somebody ought to do something about it, that's still free speech right?
That depends on a number of things. Is the subect a Public figure or not? Do you know that claim you are repeating is false? Do you have a reasonable belief that the rumor ia true? How many people are you talking to? Are you repeating the claim out of malice?