Goodreads wasn't "the future of book reviews", it was a good review site that might have innovated great new things or might not have at all. But regardless, Amazon should never have been allowed to acquire it -- it was incredibly anti-competitive. Amazon never wanted to do anything with Goodreads at all -- as demonstrated by the fact that it hasn't done anything. It was a purely defensive move to prevent anyone else…
So now any social network kind of service, which isn’t legally non-profit and open source and preferably federated, doesn’t get any cookie from me including the ones like LetterBoxd and StoryGraph.
But the problem is federated services, where you have to “choose” an instance among other frictions and all, are kinda doomed to fail. So I just use the established ones until they are unusable and keep my data regularly exported if it’s worth exporting, that is. It’s just sad.