For an annual fee, Amazon offers its Amazon Prime membership, which has perks including free two-day shipping for Amazon orders. Amazon Prime also gives Kindle owners access to a lending library; as an Amazon Prime member, you can borrow once per month directly from Amazon with no due dates. To make this happen, e-books publishers join the Kindle Select program and elect to share the book in the library; Amazon puts a sum of money up at the beginning of each month and the publishers are paid a percentage of that money if readers borrow their book.
As a Kindle owner, you can lend e-books from your collection to others for a period up to 14 days. While the book is lent out, you cannot read the book yourself, but your Kindle retains your bookmarks and other information; when the loan period is over, your Kindle remembers where you left off. You can lend any given e-book once. Lending is subject to the publisher's wishes; they can disable lending for an e-book if they choose.
More than 11,000 U.S. public libraries lend Kindle e-books. To borrow an e-book, you log into the library's website with your library card number, choose a title and have it sent to your Kindle reader via wireless Internet. The library determines for how long you can borrow a book, and wireless Internet is mandatory for downloading; the lack of support for 3G unfortunately excludes early Kindle devices from this program.
Any device that supports the .mobi e-book format can participate in the Amazon lending program. In addition to Kindle e-book readers, Amazon offers free applications for PCs and mobile devices that support .mobi. For example, you can read borrowed e-books on a Windows PC, an Apple iPad or an Android smartphone.