ImpressCMS

ImpressCMS is an open-source content management system (CMS) that is primarily focused on building websites and web applications. It`s not specifically built for advertising products or companies, but it has the flexibility to be used for various purposes, including creating advertising-focused websites. While it doesn`t offer built-in advertising features, it can be customized using plugins and modules to integrate ad networks or create custom advertising sections.

Website: https://www.impresscms.org/