It’s completely web-based and the reader can flick through cards of content when reading the book. This way, the user can easily find content again, but the main benefit is that users can comment on specific parts of the book.
I still find reading long copy on the screen a little difficult, but the idea of having an interactive book is great. Just commenting on things can be difficult in the beginning:
it occurs to me that it would be really helpful to see an outline of the book. Not just the chapter titles you’ve got above the cards, but a more detailed outline. That way, your readers wouldn’t necessarily have to read every word before making a comment that might turn out to be premature.