Microsoft has announced that it has sold over 1.5 million Windows Phone 7 devices through its various partners in the first six weeks the mobile operating system has been on the market. This is the first time the software giant has revealed sales numbers; until now, the company has been avoiding the question, leading many to believe the results were abysmal.

Microsoft says these early sales figures meet the company's expectations for a new mobile OS in an already crowded market. The company is working on multiple updates to Windows Phone 7, the first of which is rumored to be landing next month.

It's important to note that the 1.5 million number represents sales of Windows Phone 7 devices from OEMs to carriers, as opposed to devices sold from carriers to customers. Windows Phone 7 devices went on sale in Europe on October 21 and in the US on November 8. In the US, AT&T and T-Mobile offer Windows Phone 7 GSM devices. In January 2011, Verizon and Sprint are expected to begin selling CDMA Windows Phone 7 devices.

"I think our expectations are realistic for a new platform," Achim Berg, Microsoft's vice president of business and marketing for Windows Phones, said in a statement. "We started fresh with Windows Phone 7, and it's a different kind of phone. Measuring for success is more long term than short term. We launched with many of the top mobile operators in the world, and even more in the coming year in 2011. We have 18,000 developers who are developing for our marketplace. It's just getting better and better."