Flarum

Flarum is an open-source forum software, which aligns with some features of an online publishing platform, particularly in content creation and community interaction. It offers a rich text editor, community feedback tools (claps, comments), user profiles, and tags/topics for content organization. While it's primarily a forum, it can be extended for more publishing-like functionalities. However, it lacks a strong native recommendation engine for articles, and its monetization model is more geared towards paid community access rather than revenue sharing based on reading time, which are key aspects of the 'Medium' concept.