Virtually nobody knows what the hell my nickname stands for, and I don't disclose it, but it's one I came up with and now use extensively. Those people with names like Unconquerable (heh) you know are gonna be retards, although he was a fantastic player. Anyone who knows me both in person and online agrees that I am a much better person online. Anonymity doesn't always make people a fuckwad.
Plus, I am curious as to how you enforce any law, at all, on the Internet. It is even used to spread child pornography, commit terrorism, incite to murder, harass. There are a LOT more serious things going on than trolling, and none of those are stopped. How would you prevent say a site hosted in international waters, on a space station, the Arctic or Antarctic, or any country that doesn't enforce this? The Pirate Bay shows how it can be done, and even sites like Isohunt which exist in developed nations such as Canada. Hell, they even sued the Canadian record industry. Win.
The proliferation of massive organized crime (and civil violations) on the Internet shows that the law of any nation cannot be imposed here.
I am fairly sure that although such a girl would be technically guilty, not even US courts would pass a significant sentence.