Adobe Digital Editions support, which is a frequent requirement for supporting ebook downloads from public libraries, seems to be an increasingly common feature on many ebook readers (Irex, PocketBook, Kobo, etc.). See:
http://www.adobe.com/products/digitaleditions/devices/
Does Amazon plan to offer ADE support for the Kindle at some point? I know there are some kludges around that allow the Kindle to access library books in mobi format, but I am interested in official out-of-the-box ADE support.