Yeah this is spaced repetition. In this case the purpose is to memorize facts. But the asterisk method asks if you understand a concept. The purpose of revisiting asterisks is not to aid memorization via spaced repetition but to check if the understanding has improved after reading additional chapters. This seems like an important distinction.
I use Quizlet for exactly this (https://quizlet.com/). Works great. I paid for the "Plus" plan and am happy with it. (I can't recall if I needed the paid version or just wanted to support the project, but recall being pretty happy with the free version too).
Lots of great Flashcard apps out there. Definitely a great way to learn - especially things that fade quickly if not using them regularly (looking at you, Powershell ;-p ).
gwern is an amazing resource and has great articles on a range of topics, including productivity stuff; his posts on nicotine [1], modafinil [2], and melatonin [3] would be 3 highlights.
