Many of you have heard about spaced repetition. It's a learning technique that allows you to remember almost anything as long as you want. It works by repeatedly answering test questions with increasing intervals. The problem is it's not widely used (just like the art of rationality). Existing solutions are either limited to memorization of terms/foreign language words or require you to create all flashcards (test questions) yourself. But those who go through the struggle of creating flashcards for complex topics themselves show that spaced repetition can help in learning any topic.
The main hurdle to sharing flashcards is that you can't understand the question written by someone else if you don't know the topic quite well already. Therefore you have to start repetition when you understand the underlying concept. It seems that the best timing is right after you read about the relevant concept in a textbook or watch a lecture. The test question has to be integrated with the educational content.
The linked article describes the approach we take to implement this idea. We've already made a basic implementation. Now we're looking for those who want to try use it in their personal learning. But even more importantly those who are willing to experiment with creating courses for others. We'd appreciate any feedback you have!