Libel

A false publication in writing, printing, or typewriting or in signs or pictures that maliciously damages a person's reputation.  The act or an instance of presenting such a statement to the public.

Keep in mind that unlike the bulletin board at Krogers, or the Flood Control road where graffiti mixed with libel is oftentimes sprayed in paint during the early morning hours, anything written on these bulletin boards can be tracked back to the source.  So, if you use someone else's computer, or allow others to use your computer, keep this information in mind.  If you have malicious intent keep it off these boards.  If you don't the consequences could be painful to your pocketbook and your reputation!