An important question to ask is if Amazon will share technology so that other companies will use the technology. ZDNet Blogs says:

Given how collegial he is, you could argue that Amazon CEO Jeff Bezos is more the “do no evil” type and would therefore be more predisposed to allow his competitors to participate in the Kindle ecosystem than Steve Jobs is to allow Apple’s competitors to compete in the iTunes ecosystem.

Most of the article compares the iPod ecosystem to the new Amazon Kindle ecosystem.