Some interesting stuff from the DE FAQ:
What is content portability? Some users have eBooks and other digital publications on their computers that have been licensed with Acrobat, Reader, or earlier versions of Digital Editions using Easy Activation. These items cannot be moved to a new computer and are, for all intents and purposes, locked inside a particular computer. To solve this problem, Digital Editions allows you to convert items to a license associated with a named account. This allows digital content to be backed up, copied, and read on other computers. All items subsequently downloaded to an authorized computer with Digital Editions are licensed to the named account.
Adobe wants your eBook experience to be as easy and seamless as possible. Naturally, this includes protecting your eBooks from being lost or damaged. This is one of the key reasons that Digital Editions features content portability.
This feature also enables a new breed of mobile devices designed to be used with Digital Editions. Furthermore, Digital Editions will be introducing new social features in the future that will enhance the use and enjoyment of the user's eBooks, such as sharing annotations and reading lists. Use of these social features will require that you have a personal identifier, even if you only use one computer.
What are the requirements to get an Adobe ID? An Adobe ID is a free and a nonintrusive way of identifying users — you need only provide a name, country, and e-mail address. You can create your Adobe ID when prompted within Digital Editions as you authorize your computer, or go directly to the Adobe.com membership site
What is the maximum number of computers and devices that I can authorize? You can activate up to six computers and devices. If you reach the limit, contact Customer Service
to increase your allowable activations.
Why do some PDF documents look different in Digital Editions than they do in Acrobat and Reader? Digital Editions utilizes Adobe PDF technology that has been optimized for small code size and lower system requirements. This technology has shipped in hundreds of millions of mobile phones and other embedded devices. It is optimized for performance and onscreen readability, rather than graphic arts or prepress-level fidelity. As a result, some minor differences in graphics and font rendering are to be expected. In addition, the Digital Editions PDF implementation does not support several enterprise-oriented PDF features. These features are not typically used in PDF-based eBooks, and if present, they are ignored but may cause certain documents to render incorrectly.
While we all know how much DRM sucks... having something that can span devices would be nice. Of course, Mobipocket offers this but not all devices support it. The more you see and read about eBook DRM the more you realize its not about protecting copywritten material it's about vendor lockin. So, those reader vendors that also have their own store will generally only support their own DRM. But, in that case it is interesting that it looks like Sony is going to support DE... I wonder if it will support the DE DRM. We'll see.