I just learned about this app. I was surprised to see it's never hit the front page even though it's been submitted a few times. It's currently free. The featur

I just learned about this app. I was surprised to see it's never hit the front page even though it's been submitted a few times. It's currently free. The features include: - Workflowy-style infinitely hierarchical notes - Backlinks - Anki-style spaced repetition flashcards - Probably lots of other things I haven't discovered - I've only been using it for a day