Bookwyrm is specifically made for booksharing and book reviewing. While lemmy is more general. For instance, this is a link to the “a game of thrones book” https://bookwyrm.world/book/8138/s/a-game-of-thrones. Here you have reviews of the book. You can also add that book to your “to read” list aswell.

Its like goodreads but for the fediverse . A private or public book list to keep track of books and to check out what others are reading.