It's the Windows Phone 7 launch day in the United States, and mobile operators AT&T and T-Mobile are now selling the first devices to American customers. AT&T is offering the HTC Surround and Samsung Focus, and T-Mobile has the HTC HD7. All three devices are $199 with a two-year data contract.

Microsoft is positioning Windows Phone 7 devices as "a new kind of phone," and although these phones do offer the discrete app experiences common to popular competitors such as the Apple iPhone and Google Android, Microsoft's claims aren't without merit. That's because Windows Phone also features innovative new panoramic experiences, or hubs, that present multiple sources of data—like photos, music, and contacts—all in a single UI. And it includes Start screen-based live tiles that provide "glance and go" information, such as your next appointment, without requiring you to jump into an application, as you do on other phones.

The lack of this functionality on other devices is driven home in Microsoft's TV advertisements for Windows Phone, especially the popular and hilarious Really spot, in which typical smartphone users ignore the world around them because they can't tear themselves away from their phones. "It's time for a phone to save us from our phones," the ad intones. "Windows Phone \\[is\\] designed to get you in—and out—and back to life." It's a strong message, and an accurate one, as anyone with smartphone experience can tell you.

In tandem with the US launch, Microsoft has also released the results of a Harris Interactive survey, which backs up the claims made in the ads. For example, although 72 percent of respondents reported that bad mobile-phone behavior was a top pet peeve, few admitted that they personally displayed such behavior, suggesting that they're simply not aware of what they're really doing. Nineteen percent of phone owners between the ages of 18 and 24 have dropped their phone in a toilet—arguably the highlight moment of the "Really" ad—while 49 percent of adults between the ages of 18 and 24 have tripped or walked into something while walking and texting or emailing on their mobile phone.

If you're interested in getting a Windows Phone, you're going to need to move quickly. The devices sold out quickly around the world during the international launch in late October, and US retailers are already reporting that demand is going to overwhelm inventory in the United States. Both AT&T and T-Mobile will be adding additional phone models by the end of the year, and CDMA-based carriers such as Sprint and Verizon Wireless are expected to jump on board in early 2011.

For more information about Windows Phone 7, please read my exhaustive review on the SuperSite for Windows, or check out my latest book, Windows Phone 7 Secrets, which is now available in bookstores everywhere.