I’m envisioning Bookwyrm behaving as a comments section for anna’s archive (possibly all/any decentralised book repositary), but they’d be reviews instead. I’m reminded of discus or facebook that you often get embedded on certain sites.
Grayjay from Louis Rossman’s company is really good - you can even log in with youtube etc. It looks amazing. It looks like a Tachiyomi for Video and Livestreaming!!! You can add other sources.