‘Social cataloguing’ sites like Goodreads/Letterboxd/etc. allow users to record the media they read/watch/etc., usually with dates, reviews, etc. and social elements. This can also extend beyond media (e.g., Strava for cycling), but here I'm limiting my scope to just the cataloguing of discrete pieces of media.
I've been toying with the idea of developing a self-hosted, content-agnostic cataloguing tool as a personal project, using the ActivityPub standard to handle the social elements.
Does there exist any open standard that would be good for formatting the cataloguing data of a content-agnostic social cataloguing tool? Something like STIX, but instead of describing infosec threats it would be expressive enough to describe books, films, games, whatever but more restrictive than just unbounded JSON.
I've not been able to find any direct answers from online searching. The best almost-solution I've thought of so far is BibTeX, but I know from experience that that gets quite janky the further one gets from academic papers.