How profitable are link shortening businesses?

Does anyone know how profitable these types of businesses are? They seem to be able to afford to pay partners and still make profit so I've always been curious.

I am considering starting my own type of "shortening" business for my own adult traffic.

Link shortener websites typically earn revenue through advertising. When you use a link shortener service, you are often directed to a page with an ad before being redirected to the original destination URL. The link shortener website earns money from displaying those ads. Some link shortener services also offer a paid version with additional features, such as analytics and branded links, that users can subscribe to for a fee. Also, some link shortener websites may earn revenue through affiliate marketing. They may receive a commission for any purchases made by users who click on a shortened link that leads to a product or service.