Oh cool I used to use https://web.hypothes.is/ for this but they never had a good Firefox extension so I stopped. How do you annotate with friends using Margin? Does everyone need to be on the same at proto server?

The social-proofing aspects of solutions like this tend to interest me more than "building my own library"

cool, wrote a whitepaper on this called wikilay a decade ago. Definitely a way to build a better civilizations on the remnants of the slop torrent.