The MobileRead forum removed references to the software but doesn't believe the program violates the Digital Millennium Copyright Act, as Amazon charges.

Amazon introduced the second version of the Kindle in February. The devices are wirelessly tied to the Amazon store, where users can buy books, newspapers, magazines and other content. Users are restricted from loading ebooks that they buy from other sources onto the Kindle.

MobileRead had offered instructions about how to use a small script called kindlepid.py that the site didn't host but directed readers to. The script lets users of Kindles discover their device's personal ID. Many ebook sellers require the PID, but Amazon does not disclose the PID to Kindle owners, according to the instructions that were posted on MobileRead.

Armed with their PID, a user can buy an ebook on a site other than Amazon and the book will display on their Kindle. Users can also download books to their Kindle from some public libraries, many of which now offer digital books.