Defamation has been legally actionable for centuries. This is not groundbreaking. The fact that you post something anonymously does not protect you from a defamation suit. Never has and never will. If they can find out who you are, they can sue you.
Name calling is not defamation. It has to be more than mere opinion and has to impugn the character of the person spoken about. It also has to be untrue. Calling someone a slut is generally not actionable. Saying that someone slept with five guys at once and contracted an STD in the process is actionable - unless it is true.
And remember, because you can maintain a lawsuit against someone for something does not make it "illegal". That term refers to those things that are actionable by the state.
Name calling is not defamation. It has to be more than mere opinion and has to impugn the character of the person spoken about. It also has to be untrue. Calling someone a slut is generally not actionable. Saying that someone slept with five guys at once and contracted an STD in the process is actionable - unless it is true.
And remember, because you can maintain a lawsuit against someone for something does not make it "illegal". That term refers to those things that are actionable by the state.