Hack let you convert encrypted Mobipocket files that were intended for another reader so that that work on Kindle.
DRM is not to prevent other files from being readable on the Kindle.
The Kindle DRM wasn't hacked to REMOVE the DRM from Kindle purchases, but added to other books so that they too could be read on the Kindle.
There are converters available from Amazon and/or Mobi for pdf and doc files.
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.