At the risk of going off topic (and without responding to the issue of Twitter requiring real phone numbers), I want to make a point regarding your last sentence. If a post is somehow sufficient to (potentially) warrant a prison sentence (eg for leaking state secrets or inciting terrorist acts), then I would suggest the amount of time that has passed is irrelevant (within jurisdictional bounds). If a crime has been committed, responding to that within the statue of limitations is not an issue of civil liberties. Getting away with a crime (something worthy of s prison sentence) is not a civil liberty anyone enjoys.