ButterCMS

ButterCMS is a headless CMS that provides tools for content creation and management, which aligns with the core idea of an online publishing platform. It offers a rich text editor, supports various content types including blog posts and pages, and has features for managing publications (Page Types/Collections) and user profiles (Authors). While it doesn't directly offer a 'distribution and recommendation engine' or 'reader engagement metrics' in the same way Medium does, it provides the underlying CMS infrastructure that could support such features if integrated with other services. The pricing page indicates a subscription model for access to the CMS features, which can be considered a form of 'membership monetization' for content creators using the platform. It also explicitly mentions social sharing and mobile app access through its API and SDKs.