Medium launches TK: A private note-taking app built for AI collaboration

Medium is launching a new application called TK, a note-taking and journaling tool that doubles as a private social network. The most significant aspect of this launch is not the note-taking itself, but the strategic pivot toward "private blogging"—a closed ecosystem designed to bypass the declining traffic of public search engines and leverage AI agents for content management.

What happened

According to The Verge, Medium CEO Tony Stubblebine announced that TK is now available for free on web, Android, and iOS, with a desktop app coming soon. The app is described as an ultra-minimalist alternative to tools like Evernote, focusing on daily journal-style notes and longer-form writing. A key differentiator is the integration of AI models directly into the workflow. Users can type "TK" to summon a model that helps organize notes, search for information, or provide feedback on drafts. Stubblebine describes this as using "Unix pipes" to let large language models handle the grunt work of creating and managing notes.

Beyond individual note-taking, TK introduces "Libraries," which Stubblebine defines as "private blogging." These are topic-based groups where members can contribute writing, comment, and react with emojis, but there is no public face to the content. The Verge reports that early Libraries include groups sharing book projects, recipes, and poetry drafts, visible only to other members. Stubblebine argues that in a post-Google world, where search traffic is being diverted to chatbots and AI answers, public blogging is becoming less viable. He states, "I’m going to switch to private blogging… We’re just going to take everything underground." The app does not measure pageviews or reward authors for traffic, focusing instead on community feedback and encouragement.

Why it matters for small company owners and team leads

For small teams, the traditional model of documenting knowledge in public wikis or shared drives is becoming inefficient due to information overload and the lack of context. TK’s approach suggests a shift from passive documentation to active, AI-assisted knowledge curation. The "Library" concept is particularly relevant for small organizations: it creates a low-friction space for teams to share insights, project updates, and creative work without the performance pressure of public publishing.

The integration of AI agents as co-editors and organizers is a practical response to the "data swamp" problem many small businesses face. Instead of hiring a dedicated knowledge manager, a team can use TK’s AI features to synthesize scattered notes into coherent narratives. This aligns with the broader trend of AI agents acting as operational partners rather than just chatbots. By moving knowledge "underground" into private, permissioned spaces, companies can protect their intellectual property from being scraped by general-purpose AI models while still leveraging AI to make that internal knowledge more accessible and useful. The emphasis on feedback over metrics also fosters a healthier internal culture, encouraging experimentation and honest sharing without the fear of public judgment.

What to do this week

1. Audit your current shared drives or wikis to identify three topics where team members are struggling to find relevant past discussions or documents.
2. Pilot a "private library" concept for one of those topics using a simple shared folder or existing tool, inviting team members to contribute short, unpolished notes rather than formal reports.
3. Test an AI note-taking feature in your existing workflow by asking a team member to use an AI assistant to summarize their weekly notes and identify key themes before your next team meeting.

Sources

• Medium is launching a new note-taking app called TK — The Verge