DRM is not to prevent other files from being readable on the Kindle.
Non DRM Mobipocket format is already supported on the Kindle - just drag and drop.
Devices like the Sony Reader, Cybook, and Kindle DO NOT have glowing LCD screens.
Use Mobipocket software to convert PDFs to that format so you can read them on Kindle.
A revolutionary portable reader that wirelessly downloads books, newspapers, magazines and blogs to a crisp, high-resolution electronic paper display that looks and reads like real paper, even in bright sunlight.