Windows Phone 7: 40,000 Units Sold On Day One

40,000 Windows Phone 7 smartphones were sold on their first day of availability, according to a research firm.

Microsoft's Windows 7 Phone Revealed

Windows Phone 7 devices from HTC and Samsung launched Monday on the AT&T and T-Mobile networks in the U.S. 40,000 units sold in the first 24 hours, according to a source cited by The Street.com.

Although it's a reasonable tally, the number pales in comparison to the most recent offering from Microsoft's archrival, Apple. Steve Jobs' company sold roughly 143,000 iPhone 4s per day during that device's first week on the market earlier this year.

Microsoft CEO Steve Ballmer has admitted that Microsoft was late to the party in launching a smartphone OS that can support a wide range of applications while connecting users in real-time with social media and cloud services.

As a result, the company badly trails Apple, with its iPhone, and Google, which is shaking up the mobile market with its increasingly popular Android OS.

Gartner predicts the release of Windows Phone 7 will help bump Microsoft's share of the worldwide mobile OS market from 4.7% in 2010 to 5.2% in 2011, but says the company's share will ultimately decline to just 3.9% by 2014.

Microsoft will reportedly spend $400 million to promote Windows Phone 7 and is also counting on numerous partners to help it close the gap with its rivals. Handset makers include HTC, LG, and Samsung and Dell.

Windows Phone 7 also leverages many existing Windows development tools with which developers are already familiar. The downside, some critics say, is that Windows Phone 7 is not backwards compatible with any version of Windows Mobile, Microsoft's previous entry in the mobile space.