This story published to Newsvine this past week caught my eye. I'd have commented on it there, as I'm a regular user of Newsvine, if not for the comments on that story being turned off by the time I found it. One user of that site sent a rather nasty email directly to another regarding intra-site issues that need not be explained here. (You can see a screen capture of that email here.)
It was claimed by the person who wrote that story and later claimed as a fact by other commetors that the email was criminal for being hate speech and for the trailing threat, "...or hear from us". It was also claimed that the email violated that site's terms of service (here and here).
I can't say that my interpretation is complete without having the actual email to look at. I don't know that the entire message was posted in the link above. There may be more to it than has been made public, it may have been selectively edited to change its meaning, to add or remove important words and phrases, or could even be forged. For the sake of the discussion on the legality of the email's contents, I'm going to assume for now that it's genuine and complete.
Without delving into too much detail, the ToS claim fails because the email was sent directly between users, rather than using Newsvine's in-site messaging relay system. Nothing in the two usage policies governs conduct between two users that takes place off the site.
The hate speech claim fails because hate speech is protected by the first amendment, with a few exceptions (defamation) that don't apply in this case. As deplorable as it is, what is and is not hate speech is extremely subjective and well outside the responsibility and authority of the government -- any government -- to decide. What one person considers hate speech may be considered legitimate and beneficial political commentary by another. It is within a society's power to punish unpopular speech through public criticism and other powerful means that renders government regulation unnecessary, though it's still quite common in many countries.
The first amendment, as people must be regularly reminded, exists to protect unpopular speech even when it causes emotional distress. Just because someone is offended or even hurt by certain speech doesn't mean that speech doesn't have some intrinsic value.
The threat claim fails because threats of violence -- this email didn't threaten violence directly or indirectly at all -- is also protected by the first amendment. The Supreme Court ruled in Brandenburg v. Ohio that only speech directed toward and likely to incite imminent violence may be outlawed. Merely advocating violence or even issuing direct threats is not automatically a crime.
Thus, "take your bullshit somewhere else, or hear from us" doesn't even begin to approach the bar set in BrandenBurg and would be laughed out of any competent court in the country. That email was insideous and reprehensible, and at least for the moment, unarguably constitutionally protected speech.
Claims of harassment as a crime are complex and worth a lengthier discussion than I care to have here at this time, seeing as how most harassment laws are state laws (bringing into question jurisdiction) and not all states have laws that would cover online harassment via email. They would almost certainly raise first amendment questions when we're only talking about written speech, and would hardly seem to fit the description of harassment when we're only talking about a single email and, as far as anyone knows, absolutely no other contact.
In summary, as ugly as that email is, it's something that any mature adult ought to be able to take in stride and deal with. And nothing in the published contents reasonably approaches criminal behavior.