Originally Posted by HarryT
They don't. B&N use their own DRM system which is independent of Adobe. And, as I mentioned in my previous post, Apple's ebook store also uses their own form of DRM.
Add Kobo to that list, since they use both their own DRM scheme and Adobe's.
Out of curiousity: Adobe Digital Editions has an option to select an ebook vendor. Does this cut Adobe out of the loop? If so, there appear to be 30 alternatives to registering your books without going through Adobe's servers (i.e. they defined the standard for DRM, but they don't expect you to use their servers).
There are also a number of programs that support Adobe's DRM if you don't like using Digital Editions.
So yes, there are many options.