I’m using LibraryThing, after fleeing GoodReads a few years back, and I just learned about BookWyrm. I’m interested in what others apps and sites are out there for keeping track of your books and/or to-read list, and/or reviewing and/or discussing them, and what folks think about them.
I use Sofa. It’s an app only, so no social functions, but pretty useful for all medias, not just books. If the developer ever goes crazy, I can export all my lists and notes in a csv file or markdown.