I built an interactive Music Theory course 8 years ago over a winter break and it continues to bring in enough to pay my rent each month. I just thought there had to be a more intuitive way to learn music theory than the very boring and jargon-heavy alternatives. It uses Tone.js to include little interactive pianos, guitars, and other demos. I've done no marketing, it hit the HN front page for a day, and after that i…
One of the embedded videos on the progressions page is no longer available on YouTube. I'm not sure whether you're still maintaining lightnote, but thought I'd let you know anyway :)