We have taken a slightly different approach to this problem, choosing to incorporate 'note-taking' Storyline blocks at various points throughout our RISE courses. The Storyline blocks capture the learner 'notes' and, like Mike's excellent solution, we store them in the browser's local storage.
At the end of the course we have a final Storyline block that provides a button executing a JavaScript routine to retrieve the notes from local storage, open a pre-formatted pdf form and insert the notes into this 'journal' or 'course handout'. The learner is then presented with the file for download.
https://demo12.profilelearning.com
This works well but, of course, since the variables are stored in 'local storage' the learner will lose their output if they pause the course and clear the browser cache, or try and resume using a different browser, or a different device.
Like Becca, we would also LOVE Articulate to provide just a small amount of storage we could access on the RISE server so we could store variables there.