Thanks for taking the suggestion Cassius
I hope I'm not abusing your kindness by suggesting the following: Wouldn't a progress tracking bar or similar thing on a user's dashboard be great? A user could check what they've read to affect their progress and that would give us a standard to know where everybody's at.
As a gameish feature, I thing it would help engagement and continuity. In my experience, this sort of thing brings pleasure most often than not (we must have a pre conception about it 😆).