For non-technical reasons, I am closing registrations for Paperback. Paperback has been a personal project and, as such, it needs to follow personal needs and goals. I’m really sorry to do this and hope to be able to make Paperback available to new people again in the future.
I hope you understand. If you have any questions, please email support.
Update (August 2, 2019):
My good friend and colleague, Chris, is going to take over running Paperback until further notice. This hopefully won’t be permanent, but currently, I must cease involvement in Paperback. Everything will continue to work as it always has, he’ll just be fielding your support requests and hopefully maybe even fix a bug or two.