However, Verizon carried the botched Kin, which apparently has strained its relationship with Microsoft. A Verizon executive earlier this week said Verizon's business customers aren't sure what to expect from WP7. "It's fallen off the radar for enterprise customers," said Michael Tighe, Verizon's executive director of business solutions.

As with all phones, the carriers are key to a phone's success. Verizon Wireless was accused of hurting the Kin by selling the Kin phones, which did not run games, with a full smartphone monthly data subscription starting at $70, something that caused young buyers to balk. AT&T presumably will not face that problem since WP7 specifications are expected to support a range of typical smartphone apps.

Llamas said Verizon, the nation's largest carrier, could come back on board with WP7, however, possibly with a faster LTE wireless version in 2011.