Legal Question in Criminal Law in North Carolina

Based on your description, it is possible but more probably not. For a Yahoo post, nobody is really going to care unless you are threatening to blow up the President or something along those lines. But even if your post did raise an eyebrow on some nerds radar, it depends on if the post violates any laws and more importantly whether or not law enforcement can specifically identify the person who made the post. Odds are unless you were stupid enough to use your real name an address at some point the only thing law enforcement will be able to do is narrow it down to the specific computer used by tracking the IP address and / or some other geeky nerd method. Even if you did use your real name and address, this would only be circumstantial evidence as anyone could have posted using your name. Computers don't commit crimes people do - so if law enforcement comes snooping around, as long as you keep your piehole shut they will have quite a hard time making a case against you. However, if you continue to make illegal posts that have garnered the attention of some law enforcement agency, they do have ways to positively identify you behind the keyboard. So be careful what you post.