@tivasyk You might be thinking of #Goodreads with that sellout to Amazon. I migrated my data from Goodreads to #LibraryThing because I had long been uncomfortable with that at Goodreads. Also, while LibraryThing does have social aspects, it is far stronger at organizing and managing your own collection.
I looked into #Bookwyrm, which is a Fediverse project. But it was far more about social than organizing, and wouldn't have helped with my project.