One of the coolest things about Android is that you have choices. And one of the biggest choices you have is where you get your apps from. You're not chained down to just one store, and with the recent launch of Amazon's App Store, we have yet another choice.
Now to promote it, Amazon has teamed up with Verizon Wireless, and if you buy a new Android device on Verizon, they will give you $25 to use in their new store. This is also in addition to their Free-App-a-Day that Amazon does daily. This will help drive more people to the already pretty successful app store and will also help promote Verizon's HTC Thunderbolt, which just dropped to $129.99 online through Amazon.
Amazon's App Store has had a successful launch even though it is not as open as Google's Android Market. Amazon holds a more strict opinion about what apps can be released into their store, very similar to Apple's. I think it is good to see other popular app stores being releases, it will cause competition, and through competition comes creativity.