Message Walls are property of the community, not the user in which they pertain to. A Message Wall is a place for other users to send the user messages and ask questions, and to communicate when they have done something in conflict with what they have been doing, or when they are trying to settle a small issue. However, there are several restrictions regarding what one can do with a Message Wall: If a user is harassing you, talk to one of the active admins and they will close the thread and deal with the user in question.