US Patent 7865567 Virtual on-demand electronic book

An electronic book selection and delivery system distributes text to subscribers. The system provides for on-demand and virtual on-demand delivery of electronic books. Specified electronic books may be broadcast to a set of subscribers. Alternatively, a first section of the specified electronic books may be broadcast. A second section of each of the electronic books is then available for later delivery, upon order by a subscriber. The second sections, as well as first sections, and true on-demand electronic books may be loaded into one or more queues. The queues may then be emptied based on a priority model. Electronic books in an on-demand queue may be given priority for delivery over electronic books in other queues.