RE:sue sueI am sure you will be able to find a lawyer who will say there is a good chance that you will win if you lodged a claim against the poster who posted the prediction of $1000/share. That is a lawyer's opinion who will also give you their rate and approximate amount of a claim to be filed.
Now before you go to your local directory to find a lawyer you should first do your own research (which is what you should have done a longtime ago before you invested in whatever stock you bought. My mother used to say whenever I would say someone told me to do something which I should have not done "If they told you to jump off a bridge would you"). I am sure that you will not find any cases to support your argument of claim, and the most likely outcome of any claim you would file would be dismissed and you would have to pay the person you had made the claim against legal fees, plus your lawyer whose opinion happened to be wrong but they had told you what you wanted to hear.
Do your own DD is the lesson here. You may not have landed on the moon yet but could find as part of the judgement a one way ticket to the moon. If you have made the post as a threat to the poster who had made the prediction you likely have them laughing so hard they have a sore belly.