There has been some talk recently about the possibility of Amazon announcing their own smartphone. In fact, many expected the phone to be announced at Amazon's press event last week alongside the new Kindle (Fire) models. But does that really make sense? Amazon has pretty explicitly stated that the motivation for the Kindle Fire tablets is to sell other content and services to consumers. They sell the tablets cheap so that you'll buy lots of Amazon Video content and Kindle books and magazines. But will that work on a phone? For the most part, people don't like to watch movies and TV shows on their phones. Very few people read books on their phones, and magazine-style content is almost totally out of the question. Even the Amazon App Store, which has a very limited selection compared to Google Play or the iTunes App Store, probably isn't a big business for Amazon since the most popular apps are usually the free ones.
There is of course music. Amazon has tried for a while now to push their Cloud Drive and MP3 Store to only moderate success. Having a phone which depended on these services as its primary source of music would definitely help their adoption, although as more and more people switch to streaming services like Spotify I question the real profitability of Amazon's digital music business as it stands.
I'm not convinced that Amazon really has a good reason to sell and market their own smartphone. Windows Phone has shown us there's barely room in the market for a third platform after Android and iOS, and adding a fourth would only make it more crowded. Unless Amazon has some secret plan for how a smartphone will grow their business, I just don't see it happening.