Is this an invasion of privacy/against the law?

[wendy c]

Rent or no rent, this is not so much of legal issue as common courtesy.
Messages that are on your wall are visible. You know this. If you are chatting private, then they are hacking in, or you are failing to close your page. It also is a question of if you are using their computer or your phone.
As an adult.. if you want your conversation private, facebook is the worst place in the world. YOU need to be more aware. It's that simple. Either you talk verbally on the phone where there is no record or find a safer means to keep your messages truly private.