[Jane12]

Think of the CC# as a password. The reason B&N uses it is because they figure you're unlikely to share your credit card number with friends, which makes it a reasonably secure password.

Adobe Digital Editions 1.8 (which has been in beta for months) opens B&N books just fine. The first time you attempt to open a Nook book, ADE 1.8 asks for your "password," which is based on your user name and CC#. Input your name and those 16 digits, and the book opens. The same goes for any device or app that uses the latest Adobe RMSDK and has enabled password-based Adobe DRM (such as Bluefire Reader for iOS, Ectaco's jetBook Lite, Pandigital Novel). No pesky ascm files and content servers to contend with. Just download the epub from the vendor, and you're good to go.