I can't actually try it yet, since it's invite only, but it's an interesting concept. I mentor a lot of people learning programming, and one of the key problem

I can't actually try it yet, since it's invite only, but it's an interesting concept. I mentor a lot of people learning programming, and one of the key problems they tend to face is that a week between sessions gives them plenty of time to forget what they've just learned. This is potentially one arrow in the quiver of slowly building up and reinforcing that knowledge in a passive way.