In the US, you can get hit for defamation even of a public figure if you made the statement with "reckless disregard for its truth or falseness". You don't have

In the US, you can get hit for defamation even of a public figure if you made the statement with "reckless disregard for its truth or falseness". You don't have to know for sure that it's false. Either knowingly lying or "reckless disregard" is "actual malice". Private citizens need to prove actual malice to collect punitive damages, but mere negligence is enough for compensatory damages. That's for knowledge about the statement itself; I'm not sure what you have to know or intend about how much damage you'll do. That's constitutional standards; there may be state-to-state variations that impose more conditions. On edit: corrected; even for a non-public figure, it needs to be negligently false, so having taken reasonable steps to verify it should immunize you. But of course this kid clearly did not do this.