I've been using Anki flashcards for about half a year now as a spaced repetition memorization app. I have about 800 notes covering anything from tech, politics, and personal/social stuff I want to remember and keep reasonably fresh in my brain.
It works great for what it is, but having successfully maintained a habit of doing a daily Anki review for 6 months, I see the shortcomings of this approach: I can correctly "answer" the flashcards, but my understanding of underlying content and network of ideas is quite shallow. I'd hoped that by keeping the peripheral flashcard-able ideas fresh in my brain that that would strengthen the underlying conceptual bonds, but unfortunately that isn't the case. (And frankly, the fact that I could keep this habit so easily makes me feel like maybe it was a lazy half-ass approach to feeling like I was deeply learning.)
So it's on to the next thing. Perhaps variant of the Feynman method?