I have information on a co-worker, and we're both up for a promotion. Whether it's unethical or not doesn't matter, but I'd like to know if I can get in legal trouble.
If you have true information about someone that you release and it does non-physical harm to them you have not done anything wrong. However, if you demand something from them in return for keeping quiet then yes you can get into legal trouble.
I do not think that it is illegal to blackmail someone. They should have not done wrong or said anything for you to have to blackmail them with of course.
Blackmail is defined as threatening to reveal something embarassing about a person unless the person gives the blackmailer something of value. It is a form of extortion, and therefore, illegal.
