| 摘要 |
An electronic book system allows third parties to make available to users extensions, or “add-ons”, that provide additional features and functions relating to a book. Add-ons are launched in a manner that takes into account the reader's context, such as a current page the reader is looking at. Payment mechanisms as well as policies for the add-ons are integrated so that restrictions imposed by both book publishers and add-on publishers are respected. |
