@Austin The impactful ones have really been Anki (and memorization heavy stuff like it, to your point) and Notion I might count as a "tool-for-thought" as well, although sort of in a different domain.

I also agree that "making friends" could perhaps benefit from SRS-style thinking. I started an Anki deck for this purpose actually hahaha, but the UX is hard to nail, and I haven't ended up using it much.

I think you make a lot of interesting points. Thanks for sharing.

@Austin Hey Austin! I definitely hold some of the same reservations as you here, and have been similarly skeptical. Yet, I have to admit that a few of them have actually been very impactful on me / the world. I'm curious what you think makes the difference between the projects that succeed and those that don't or if you have more to add there.