I've been using this for a bit and have some major complaints, the primary one being that reviews and books aren't shared across all servers. I'm still going to use it to track my reading, but the "social" aspect is straight limited from the start. I want to see ALL reviews for a book, not just the people I follow or the ones on the server I joined. How do you even find people to follow with that level of visibility?

This thread talks through it. https://fosstodon.org/@Brendanjones/110722850962870241

Edit: It's still way better than feeding your data into the maw of the ever-hungry Amazon, but I want it to be something I can recommend to my non-technical reading folks.