As I have previously written, and discussed on the Windows Weekly podcast, platforms matter. But the technology choices we make are not just about platforms. They're also about ecosystems.

When Nokia CEO Stephen Elop announced his company's intention to focus primarily on Windows Phone going forward, he offered up an interesting commentary about ecosystems. Platforms and ecosystems aren't interchangeable terms--A platform's ecosystem can often be seen as a superset of the platform itself, from a functionality or feature perspective--though people often confuse the two. But Elop's claims about the important of an ecosystem is well argued, and when it comes time for you to make your own decisions about many tech products, factoring in the relative strength of that product's ecosystem makes sense.

The Windows OS is, for example, a platform. But on the SuperSite, and in my Windows Secrets books, I've approached Windows as more than just that product that Microsoft delivers largely to PC makers and to some individuals in retail boxes. So I cover the broader Windows ecosystem, which includes Microsoft (and third party) add-ons like Windows Live Essentials, Microsoft Security Essentials, and Zune. These and other ecosystem products and services "complete" Windows in the sense that they speak to the broader advantages of using Windows than does just using Windows by itself. And that's because no one uses just Windows. The platform is the core part of the ecosystem, but it's still only a piece of a bigger puzzle.

This is true of mobile platforms as well. And when you look at today's smart phone market, one inescapable fact emerges: The superior platform, overall, is Apple's iPhone. And the reason has only a bit to do with the strength of the device itself. Instead, it's generally superior because Apple's supporting ecosystem is so strong. The iPhone is supported by the biggest and best app store, the biggest and best content store (the iTunes Store, which includes music, movies, TV shows, podcasts, audiobooks and eBooks, educational material, and more), the broadest and most impressive collection of hardware peripherals, and more.

The iPhone has only one viable competitor at this moment, and that's Google's Android platform. But while Android is currently outselling the iPhone due to its far more diverse device selection and broader wireless carrier distribution, even Android doesn't come close to what Apple offers to iPhone users. Yes, individual Android phones--which seem to appear at a rate of about one new device every week--may beat the iPhone in certain areas, like 4G support, larger screens, or whatever. But Android as a whole--that is, not just that device but also the supporting ecosystem--simply falls short.

There are two key areas where this is the case, I think, and for many people--myself included--these areas are the deal breakers, the big reasons to ignore Android and focus on other platforms. (For most, this means iPhone, but other platforms like Microsoft Windows Phone, HP/Palm webOS, and RIM Blackberry also offer some respite from the chaotic Android world; these platforms of course fall far short of iPhone as well, however.)

These two areas are app discoverability and purchasing (i.e. the Android Market) and digital media (in that Android lacks anything even closely resembling Apple's iTunes Store).

These are insurmountable issues for many smart phone users, and while some may not want or need seamless access to a wide range of digital media content--they're either terribly boring or too technical to care--smart phones exist, primarily, to run apps. Yes, we make phone calls and send and receive SMS messages. But smart phones are a vehicle for apps as surely as popcorn is a vehicle for butter.

Android's lack of a seamless and pervasive digital media solution awaits a future fix, but this week Amazon released its own app store for Android, called the Amazon Appstore for Android, that neatly solves the first issue I raised. And it makes Google's own offering (the Android Market) look so sad by comparison that the Google would be doing its customers a favor by simply discontinuing it and ceding this functionality to Amazon. They'll never do this, of course. But they should.

Amazon's Appstore is so good, in fact, that it puts Android within striking distance of the iPhone for the first time, from a functionality and desirability perspective. This is a position the other smart phone platforms will never achieve, ever. It's just impossible. Apple's lead is simply too large, it's ecosystem--which also encompasses the iPad, iPod touch, the Apple TV, and other products, too, remember--seemingly unassailable. But suddenly, Android is right there, close. Thanks to Amazon.

Stepping back for a moment, I'd like to introduce another related strength of the iPhone ecosystem: Thanks to Apple's expertise at online commerce, it's incredibly easy--maybe too easy, as with in-app purchases--to find and buy content (apps, media, etc.) that work with Apple's products. Not just the iPhone, but all of Apple's products. So if you're on the road, and want to rent a few movies to watch on the plane ride home, Apple's got you covered. And you can choose between several devices, including PCs and Macs, iPods, iPads, and iPhones. At home? Stream the movies from your iPad to the Apple TV. The benefits are vast. Global in scope. And so complete as to render the competition almost laughably inept by comparison.

The key to this whole system is an account. And as you look out across the Internet at the various accounts you may have, there are only a handful that are absolutely key to a broad majority of users. Facebook, perhaps. Apple's iTunes Store account, certainly. Your email account.

And then there's Amazon. As the years roll by, my Amazon account has become more and more valuable as the company has added numerous benefits, many of which may be surprising to you if you weren't really, really paying attention. Adopt Amazon's Kindle platform and whatever eBooks you buy are available going forward on not just Kindle devices but an ever-expanding range of devices. Buy software electronically from Amazon and you can redownload it anytime you want to different PCs. Ditto for movies and TV shows (though you may need to stream them going forward if you exceed a certain number of devices.) The company offers excellent quality MP3 music files too.

And now it offers Android apps.

This means you can purchase Android apps from your PC's web browser and have them appear immediately and automatically, on your Android device(s), ready for installation. Or, you can browse for apps and download and install them directly on your Android device.

These apps are tied to your account--i.e. to you--and not to a particular device. So as you move to a new phone in the future, or perhaps add an Android-based tablet to the mix, all you need to do is install Amazon's Appstore app on your device and--voila!--your entire app collection is ready for installation. Automatic. Seamless. Breathtaking, really. It makes the Android platform suddenly much more interesting, and viable as a replacement to the iPhone for many users.

Amazon's eCommerce prowess shows up in numerous ways here. Excellent store navigation with great search and various lists (bestsellers, hot new releases, movers & shakers, categories and more). Curated apps, not the crazy collection of crap that Google just allows through to its own store. One-click buying. Extensive and meaningful user reviews. Exhaustive product information, including screenshots, and, eventually, in-browser trial runs using an Android emulator. Device management. App management. Plenty of documentation. And get this, real support.

Amazon also offers Appstore gift cards which you can email, send via Facebook, or even print out. So now it's possible to give the gift of apps to other Android users, or provide your kids with an allowance of sorts.

Temporarily, Amazon is also providing one paid app each day for free. This is a great incentive to check out the store if you're an Android user, and should jumpstart this effort nicely.

And for you developers in the audience, Amazon has extended its existing developer program to include a new Android entry. Like competing smart phone developer programs from Apple and Microsoft, Amazon's costs $99 per year. But if you sign up now, the first year is free. And let's face it, Amazon.com isn't such a horrible place to sell something.

For all the goodness, the Appstore is new. And as such, it's not perfect.

The Android Market is infamous for low-quality apps of dubious intent, and as Steve Jobs once pointed out when pressed about the highly curated nature of his company's App Store for the iPhone, if you're looking for mobile porn, Android is your solution. So I was expecting Amazon's entry to be cleaner than Google's. And it is. But I very quickly did come across some very dubious adult titles, which surprised me.

The Appstore is still new, so it falls far short of Google's collection of 170,000 apps (or whatever). There appear to be about 4,000 apps in the Appstore, however, and at least they're curated (though again, adult apps are available).

Currently, Amazon's Appstore is US-only, though Amazon intends to expand it internationally. I expect this to happen quickly.

And finally, for the moment at least, AT&T users are not able to access the Amazon Appstore, or those apps, on their devices. Amazon and AT&T are working to remove this limitation, and I expect that to be solved in the weeks ahead.

If Google can do something about the digital media stuff--there's rumor of a planned Google Music service, for example--the company's platform could almost run neck and neck with the iPhone. Until then, Apple's platform is the one to beat in my book. But this Amazon service really resets the equation in a big way. If you are using Android (and are in the US), I recommend jumping on board quickly, if only to take advantage of the daily paid app for free.

The term game changer is tossed around a bit too casually these days. And let's face it, Android was already winning. But this is a big deal. A very big deal.