Unfortunately, I don't think this would work. The barrier of the internet creates too much plausible deniability. Remember, to convict someone of murder, you have to prove their guilt beyond reasonable doubt. It would be really easy to falsify circumstances if you were the only person present IRL when you posted the message. Example: whose to say you weren't drunk?KyuubiNoKitsune-Hime said:Stuff like this is why I'm of the opinion that driving someone to suicide should be considered first degree murder. It's not right that people get away with harassing someone until they commit suicide, this sort of thing needs a really harsh punishment, to make those who do the harassing think twice. If they're too stupid to think twice, put them in prison for life as an example to others that this kind of hateful bs is not okay.
There's also a problematic grey zone when it comes to mass harassment: Who are you going to convict? Everyone who posted a sufficiently vicious comment? Can you draft a logical, objective standard for what counts as "Vicious" that would be internally consistent and broad enough in focus to be admissible in court?
Intent presents the biggest obstacle; if we acknowledge that internet comments can either be utterly meaningless in certain circumstances and constitute attempted murder in others, how do you prove that the defendant had murderous intent? Especially considering that you would often have no way of knowing whether or not the defendant had intimate knowledge of a stranger's psychological or medical conditions at the time of posting.
Something else to think about: A law like this could create a dangerous slippery slope. If you can be lawfully convicted of murder based on internet comments, how easy would it be to admit them as evidence in a case where someone is being FALSELY convicted of murder?