Medium launches TK, a private writing app for members

TK combines quick notes, journal entries and longer writing with tools to organize and search a user’s work. Users can ask an AI model to find material in their notes or offer feedback. Typing “TK” summons the model to fill in information, using the letters as a searchable placeholder familiar to writers.

The app’s social feature is called Libraries. Users can contribute to topic-based spaces that Stubblebine describes as “private blogging.” Groups can share projects, recipes or poetry drafts with members, while collaborators can also work on individual writing through links or email, leaving comments and emoji reactions. The approach is intended to encourage feedback without relying on pageviews or traffic incentives.

Stubblebine links the launch to Medium’s wider shift away from advertising. In 2017, then-CEO Ev Williams moved the company toward subscriptions, arguing that ad-driven media did not serve readers. Stubblebine says search engines and chatbots now send less traffic to websites, while AI firms use online content. Medium depends heavily on Google referrals, he said, making that decline a risk. TK, he added, can operate without Google directing visitors to it.

The app is currently available to existing Medium members on the web, Android and iOS. Stubblebine says a native desktop version is coming, and that some TK features will reach Medium. He also sees possible revenue in private or paywalled material, including charging people or AI agents for access to curated collections. TK is part of his argument that future AI systems need a layer of human-created knowledge.