Sao Paulo, Brazil, has banned outdoor advertising. The ban, which covers everything from billboards to signs on taxis and buses to fliers passed out on the sidewalk, takes effect at the start of 2008. The law also regulates the size of store signs. Those who break the law face fines of up to $4,500. That's assuming it stands up to court challenges. A provision banning signs flown from airplanes has already been struck down.