I want to say trolling is somewhat like obscenity—in that you know it when you see it—but that is a deeply unsatisfying response when so much discourse online is so polarized.
Because it’s Ok for me to disagree with, even hate and detest, what someone is saying. It’s Ok for me to shocked and angered and deeply offended by a thing you say. It’s not Ok for me to go around clubbing people when they do this.
I think the current laws on libel, defamation, and slander are appropriate and fairly functional. Public figures in particular have a higher burden as well they should.
The new generation of anti-speech laws here and in the UK I find are deeply flawed and dangerous, and appear to me to be tools of oppression rather than the opposite.