That is a very cool idea! I've been thinking about something like that to help fund the website, which is a network of book trades, and you get credit for a new used book for every trade. Although I was going to charge $10 a year or $1 a book to go 80% toward authors and 20% toward the website.
> Do you use something like openlibrary.org as well?
When I last looked in 2020, the data quality on open library was really bad, so I didn't use them. We created every book recommended in our system manually, as we needed to find high-quality cover images, and it was an easy way to start.
Eventually, we licensed data from the Nielsen API. It has not been a great experience, but it works "ok." I also looked at Ingram and Bokwer. Now things are 90% automated, but we still have to source a high quality cover for each book as the book APIs have such small images.
I am hoping to expand our book DB in 2025 to all books for a lot of the new features. I am going to look at Open Library again then, as it might work better for that limited functionality. I also could have been too pedantic back in 2020 when i looked at them :)