I know a programmer who 15 years ago made a PHP program that that made hosted directories. I don’t think it ever got out of beta but it was stable and I tested it by making a little directory on it and running it for a few years. All one had to do was register and you got a subdomain directory with a simple control panel for adding categories and sites. A lot like WordPress.com only for directories. It worked fine.
It checked all the buttons: no script to install, easy to sign up, easy to make links and easy to use. But it wasn’t pretty and I don’t think he ever figured out how to monetize it.