As I write this, I'm at the MIX10 conference in Las Vegas, where Microsoft is telling the world its developer stories for Windows Phone 7 and Internet Explorer (IE) 9. I'll be covering these developments all week. But last week, in a small meeting room on Microsoft's ever-expanding Redmond campus, I had a much more exciting opportunity. I finally got some hands-on time with Windows Phone 7.

And exciting is absolutely the word for it. Looking back over the past 15+ years of covering the tech industry professionally, I can recall only a few moments of actual excitement and even fewer where the initial buzz didn't die down as quickly as it came. But Windows Phone is a game changer, and that's something that we can't say all that often about Microsoft products. The fact that it comes so soon after the iPhone—itself a game changer of historic proportions—and competes in the same market is, perhaps, most astonishing of all.

There's a lot of marketing hoo-hah around Windows Phone. Spend any time investigating this platform and you'll hear terms like "delightful" and "smart design" repeated again and again. But Microsoft isn't just shaking it for all its worth for marketing's sake. Its previous mobile platform, Windows Mobile, is a dud after a decade of neglect. And as exemplified by the iPhone, the smartphone market has suddenly heated up. This market will quickly outpace the PC market in terms of both volume and annual revenues.

Microsoft could have taken the easy way out with Windows Phone. In fact, it was previously working on Project Photon, which would have become Windows Mobile 7 and done just that. But instead, it did something that the software giant so rarely does: the right thing, which in this case, means starting over and righting the wrongs of the past.

A list describing those wrongs would be long enough to fill a book. I don't have that much space, so let me deliver some highlights. Let's start with the most obvious element of this system: the thing that you'll look at and touch. This is the user experience.

In the wake of the iPhone, other smartphones have fallen into a familiar (if not old fashioned) single-tasking application-centric approach, marked by a grid of icons, each of which provides access to a single function such as Facebook or email. On Windows Phone, Microsoft has stepped back and reengineered the system to accommodate the user instead of the applications. That means an intelligent and dynamic Start screen that—God help me—is actually delightful. And useful, which is perhaps more important. It means that if you want to view photos shared on Flickr, Windows Live, or Facebook, you just navigate to a beautiful Pictures hub, a panoramic experience that aggregates content from multiple services and applications. You don't have to dive in and out of individual applications to view this material separately and disjointedly. Smart.

From a hardware standpoint, Windows Mobile is a mess. There are likely no examples of any human being walking into a wireless store and declaring his or her desire to buy a Windows Mobile phone. Instead, some people end up with Windows Mobile phones because those devices meet some need. More often than not, some third party (a wireless carrier or phone maker) has obliterated the Windows Mobile UI and replaced it with a front-end of its own. (And if there is any sadder commentary on the state of Windows Mobile right now, I can't think of it.) Windows Phones will be consistent. There will be two screen sizes: 800x480 screens (which is all we're seeing right now) and later smaller 480x320 screens. The UI cannot be replaced by a third party. Instead, wireless carriers and phone makers can add their own hubs and applications and not muddy the work Microsoft has done. The list of required hardware is long, rigid, and wonderful:

  • A capacitive touch screen with four or more contact points
  • A full complement of sensors, including A-GPS, accelerometer, compass, light, and proximity
  • A high-quality camera (5 megapixels or more) with a flash and a dedicated camera button
  • 256 MB RAM or more and 8GB or more Flash memory
  • A DirectX 9-capable GPU
  • An ARMv7 Cortex/Scorpion or better processor
  • Three hardware buttons (Start, Search, and Back) on the front of the device in the exact same location

A hardware keyboard, it turns out, is optional. That's because there will be multiple device form factors, giving users choice where it matters most. So when people go into the stores and declare their desire for a Windows Phone experience, they're going to get it. And on a range of devices.

Another long-time annoyance with Windows Mobile is the software updating process. For reasons that have long benefitted its mobile industry partners and harmed users, Microsoft has never allowed Windows Mobile users to update their system to new software versions. (Very, very few device makers and wireless partners ever provided any upgrade paths of their own.) The reason for this is simple: Wireless companies make more money when you buy a new phone—and thus reset your contract out another two years—than they do by providing users with free updates. So that's been the model.

Not anymore. As Apple does with the iPhone, Microsoft will "own" everything about the Windows Phone user experience. This includes the UI, of course, but also some other things—such as device drivers and the phone dialer—that the company previously farmed out to device makers and mobile operators. And, thank the heavens, this also includes the updating process. So with Windows Phone 7, Microsoft can and will deliver critical and other software updates via a Windows Update mechanism, up to and including updating any and all of the software that's preinstalled on the device. Bravo.

For developers, the picture is rosy, too. Windows Phone supports two primary development interfaces. There's XNA for games and Silverlight for more traditional applications. Silverlight is essentially a Windows Presentation Foundation (WPF)-like presentation framework on top of .NET. We're talking Visual Studio for coding, Expression Blend for UI design, and programming models that developers already understand. Best of all, those wanting to get into Windows Phone development can do so for nothing—the tools are all free—and then get their apps hosted in a new Windows Marketplace environment that will surprise people. (It's available both on the phone and on the PC, in the latter case via Zune software.)

And before any of this scares off you enterprise/business customers, relax. Microsoft hasn't forgotten how it got here, and Windows Phone will offer the most compelling smartphone feature set it's ever delivered for businesses. It will have new versions of the Office Mobile apps. Direct integration with SharePoint. Support for multiple Exchange ActiveSync accounts, providing seamless integration of business and home email, contacts, and calendars if you want it. And this summer (I'm thinking around the time of TechEd 2010 in June), Microsoft will announce that businesses can deploy internal Windows Phone applications privately using an as-yet unnamed "common distribution system." I'm guessing this means Windows Server Update Services (WSUS) or System Center Configuration Manager (SCCM).

Windows Phone combines those very few things that were right about Windows Mobile—primarily some business functionality—with a much wider set of new functionality that's exciting in both scope and possibilities. And that's the thing about Windows Phone 7. I can't shake the feeling of excitement, and while I keep waiting for some unfortunate bit of reality to come crashing down and ruin this vibe, it's lasted far longer than seems reasonable. It's been a long time, it really has.