Billboards are banned where I live and it's great. It's interesting that this post says that where the author lives "someone can put up a 48-foot advertisement wherever they want". From other things I read I got the impression that in some (maybe many) cities a reason they're not banned is because they provide revenue, since many are on land like road medians that are controlled by local government. I'm not sure to what extent the designs themselves are reviewed but the ability to erect a billboard is regulated in such cases.