Mixed messages in early sales figures for Windows Phone 7

Microsoft's reboot of its smartphone division seems to have suffered a major setback in its first real test, apparently selling only 40,000 Windows Phone 7 devices on the day of its release in the US - despite an estimated $100 million marketing budget.

That figure is spread across nine different models of smartphone supporting the new OS and architecture, between the two US carriers currently stocking the phone - At&T and T-Mobile.

The figure was reported by business site The Street, which cites its source as a 'market research firm' but does not give details. No international figures are available.

To put that figure into context, Apple claims that 270,000 iPhones are being sold each day, internationally, while Google puts the daily sales for its Android phones at around 200,000.

"It's early in the game," Nielsen telecom analyst Roger Entner told The Street. "Not every product surges right out of the starting blocks. The first Android phone was not a big seller at T-Mobile."

"We'll see what happens with Black Friday sales. They'll probably cut prices like everyone else does. It's the nature of the beast. The only one that doesn't do promotions is Apple."

However, many retailers and twitter users posting with the #WP7 hashtag were reporting sell-outs across the US and in other territories. Microsoft and the US carriers have declined to publish any official sales figures for the phones.

Windows Phone 7 offers customers integrated Xbox Live and Games for Windows Live support - a feature countered by Apple's Game Center feature.