https://joinbookwyrm.com/
is your library connected to the library of other through fediverse. You can track your readings, your want to read, have read, reading challenges. You can follow others in their reading.

It is like goodreads but without evilcorp owning and monetizing your data and behavior.

How could this look like?
Your activity in the app could be synced to your bookwyrm account. The app could show what your bookwyrm instance notifies you about.