SubHub

SubHub is a platform designed for creating and managing membership websites, which aligns well with the concept of an online publishing platform that monetizes content. It offers features for content creation (though not explicitly a 'rich text editor' in the same vein as Medium, it supports various content formats), membership monetization, and tools for member engagement and management. While it doesn't have a direct 'recommendation engine' like Medium, it provides tools for content organization and discovery. The platform's focus on selling access to content, courses, and events through subscriptions strongly matches the monetization aspect of Medium.