Having a dedicated section for each book to save and mark down quotes while reading and/or while reviewing would be incredibly helpful. Maybe it could sit on a book's page when the status is currently reading or read, and you can add as you go along, marking what page it's on etc and adding any comments. Being able to see other people's quotes and takeaways would be amazing as well - potentially in the side underneath where you can see if friends have read the book or want to read, there is a section to see their quotes, as well as random community ones, and an option to scroll through all collected for the book from the wider community and comment on them. At the moment, I've just been saving mine in the review, but really wish there was a dedicated space!