Amazon's ebooks only work on amazon hardware.
Not entirely accurate--one of the things I like best about ebooks from Amazon is that I can (and do) read them on the Kindle, my phones, and my computers. The Kindle app is available for just about everything, and syncs between devices so I can pick up on one where I left off on another.
The second rule of Seattle Club is: YOU DON'T TALK ABOUT JULY AND AUGUST!
(An exception to rules 1 and 2 is being made for 2011).