James Martin/CNET

Mobile is the future, and nobody wants to be left behind, because losing would mean certain death.

The iPhone accounts for a whopping $150 billion of Apple's revenues over the last five years. Google spent $12.5 billion in order to acquire Motorola. Microsoft and Nokia have finally built a flagship Windows phone (though they seriously need to fire whoever named it).

Amazon is the company everyone should be watching in this space, though. The online retailer first struck gold with the Kindle e-reader in 2007. A few years later, Amazon decided that Apple and Google needed some competition in the tablet market, so it released the Kindle Fire, a well-reviewed $200 device with a 7-inch screen.

On Thursday, Amazon upped the stakes further with the Kindle Fire HD, a tablet with an 8.9-inch screen; improved hardware and graphics; and a reasonable $299 price point. It's a very vocal response to Google's well-reviewed Nexus 7 tablet. Oh, and did I mention that Amazon is reportedly working on a phone as well?

Why does Amazon care so much about being in the hardware game? I think CEO Jeff Bezos came to the same conclusion I made several years ago when it comes to smartphones. It goes something like this: He who controls the hardware, controls the platform. He who controls the platform, wins the war.

E-books are becoming a bigger and bigger part of Amazon's business, but it has to play by Apple and Google's rules when it makes apps for their platforms. Amazon, for example, can't sell e-books in its iOS apps, unless it wants to implement in-app purchases and give Apple a 30 percent cut of its e-book revenues.

On Kindle tablets and e-readers though, Amazon gets to create the rules and keep all the profits. It can control the user experience and up-sell its e-books and multimedia content.

That's why Jeff Bezos isn't about to allow Apple, Google, and Microsoft to dominate mobile. It has already made a big statement in the tablet market. And with its huge distribution and pricing strategy, you can be sure it's going to ship millions of Kindle Fires and Kindle Fire HDs.

It's the almost inevitable Amazon smartphone that intrigues me the most, though. If you think Bezos is going to sit the smartphone market out, you're nuts. Consumption is increasingly occurring on smartphones, and Amazon's CEO knows that his company will need smartphone hardware of its own to accelerate the growth of its e-book and multimedia businesses.

If Amazon can create a comparable smartphone with plenty of cloud features, easy access to Amazon content, and a low price point, it has a shot of upsetting the smartphone game. Never underestimate Amazon's distribution and marketing prowess.

I think the message Bezos delivered on Thursday was this: Amazon is coming after you, Apple and Google. Be afraid.