Legal Question in Technology Law in Missouri

Yes, they can. In the US anybody can sue anybody for anything. Whether they can win (force the release of your identity) is the real question. Initially they would sue you as a "John Doe" or an identity/name used on that website and seek an order to authorize the release of your identity information. You would be able to appear under your website identity/name to defend against the subpoena. Unless they have stated an enforceable cause of action the subpoena would be denied and the action could be dismissed. As the action would on its face be without a legitimate basis it could well be treated as frivolous and therefor subject to sanctions. You should consult with an attorney licensed in Missouri if that is where you would expect the action to be filed if it is filed. (Feel free to contact me for a referral to an attorney in Missouri if no Missouri attorney answers this question.