Chrome extension. Under development.
Cairn is a Chrome extension for people working through real university lecture series — Stanford CS, MIT OCW, and the rest. It tracks your progress across devices, and surfaces traces left by other learners who came before.
How it works
Track your progress automatically.Cairn watches what you watch on YouTube and tracks it against your enrolled courses. There is no "mark complete" button to click. Sign in and your progress follows you to the next computer, picking up where you left off — at the second you left off.
Find traces from other learners.When you reach a hard moment in a lecture, see notes left by people who were there before you. Each trace is anchored to the second it was posted. It is not a chat — it is a marker on a trail. You can leave one of your own and keep walking.
Pick up on any computer.Sign in with Google and your courses, progress, and notes follow you across devices. Watch a lecture on your laptop, finish it on your work computer. No account needed if you'd rather keep things local — Cairn works fully offline as a guest.
What's different
Cairn is built around the idea that other people walked this trail before you, and what they left behind can help. Most YouTube tools are built for the solo note-taker.
A trace is a short, timestamped note pinned to a moment in a lecture. You see traces only at the seconds they were posted, and only when they are useful — at the kinds of moments where someone reached out a hand. There are no follower counts, no DMs, no replies threading off into the woods. People appear under anonymous nicknames they choose.
The course catalog grows from the people walking the trail. Anyone can add more.
Honest about what this is
Cairn is a free side project. It exists because the person who made it kept abandoning Stanford CS and MIT OCW courses around lecture four, and wanted a tracker tool that is accessible. If that's you too — welcome.