One curmudgeon's reaction ...
I'm sure it's wonderful. I use MarkDown to take notes, I link them together, and I use Spaced Repetition systems to learn and review. Having everything linked together in a single system is potentially interesting and useful. This looks like exactly the sort of thing I am primed and ready to use.
It says "Start Learning for Free", and then I need to sign in with an email and password, or with Google.
Without knowing more about it, how it works, where things are stored, what it does differently from everything else, what your privacy policies are, whether I can import/export data, and without actually trying it, I'm not signing up.
Closed.