If this was the whole story, they he'd be fine. Not harassment, not libel, not a violation of privacy.
But looking into it a bit, seems like this isn't the whole story at all. The billboard originally had a thing at the bottom that said "Created for N.A.N.I." which stands for the National Association for Needed Information or some shit. It's an organization he made up himself. Which also happens to be his ex-girlfriend's name
(Nani). He changed it after the charges were made against him.
It was also said at numerous different sites that she was only 18, possibly younger at the start of their relationship. Also appears like he has previous history of harassing her. Which will fuck him in court if true. She was also granted a restraining order on him. He supposedly has a twitter account where he posted crazy shit about shooting ex's and shit. But I don't care enough to verify that shit by actually going to the twitter website, because fuck twitter.
Here is a link where you can see some of his tweets:
Holy shit, this guy.