Comment by dlwiest

There's very little speech that's actually illegal in the US. You can't tell outright lies about someone with the intention of hurting them professionally (although it's still a civil matter, and when I say "lies", I mean specifics, e.g. you can't claim in an article that someone dropped out of college if they didn't) and you can't say anything that has a high probability of causing immediate physical harm (e.g. you can't order somebody to shoot someone). That's basically it. When you start talking about publishing photographs or recorded audio, things get a bit more complicated because of copyright laws, and obviously CP is illegal, but strictly in terms of speech, online or off, there are almost no restrictions here.