Kindles can read a variety of non-proprietary, non-DRM'ed formats. They read TXT, HTML, JPEG, and non-DRM Mobi files directly.
The Kindle has many flaws, but it does allow you to read a few different non-DRM formats.
The Kindle only allows the reading of Amazon DRM-protected content.
Hack let you convert encrypted Mobipocket files that were intended for another reader so that that work 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.