The system used to set up personal or group challenges?
An area per user you can fill with your own content sounds interesting. There are a lot of “lesson progress” threads on the forum, and from time to time people post links to blogs they’ve set up documenting their Welsh learning journey, but unless you’re willing to scroll back in time through the forum all that stuff might as well not exist.
Something to bring all that together, or provide a place where it can live permanently, has a nice ring to it.