DRM is not to prevent other files from being readable on the Kindle.
There are converters available from Amazon and/or Mobi for pdf and doc files.
The Kindle is already able to read more than just Amazon DRMed content, it can handle a number of formats.
Devices like the Sony Reader, Cybook, and Kindle DO NOT have glowing LCD screens.
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.