@spgreenhalgh Using Hypothes.is as one's commenting system is one of the most bleeding edge fancy things one could be doing. Now I'm sort of regretting my first "comment" on your site wasn't: "First!". 😄
Beyond their social annotation features, I've been using it primarily as a note taking/excerpting tool in the vein of the "forgotten" but related practices of commonplacing and zettelkasten (card indexes).
See, for example: - Creating a Commonplace Book by Colleen Kennedy - How to Take Smart Notes: One Simple Technique to Boost Writing, Learning and Thinking by Sonke Ahrens
On the side I'm working at putting these into a broader pedagogical practice.