new old in between wrote:
They can't get that specific.
They can get specific enough to determine which IP address you're using, and find out which ISP owns that block of addresses. That's actually very simple.
From there, the ISP should be able to provide records of what home was leased that IP address at the time of the posting. Now, making the ISP give up the information is a whole other matter. I have no idea about what authorities one would contact (DEA comes to mind), and I imagine it might take a court order for the ISP to hand over those records, but they most definitely can get that specific.
Now that's all assuming the brojos could get his actual IP and he's not using some anonymizer service. If he is, court orders might still get what they need, but who knows. Unless you're making use of some proxy servers outside the US, I wouldn't count on any anonymity online. Come to think of it, I wouldn't bank on it even then.
That all said, this kids's probably a troll anyway.