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.

I requested a code on the site and was told I was "at position 1163 in the queue." I received a code three days later.

I can't comment much on the app yet since I've only done one session so far.

'request an invite' is setting yourself up to fail to start with. Much like what happened with Ello, it catches your attention, I'm reading this article, I'm aware of it but if I have to request an invite and wait 3 days I'll have forgotten all about it by then and won't be interested anymore!