It was rumored before that Microsoft's new Windows Phone 7 might not be initially launched on CDMA networks, as widely used in the U.S. and now, Greg Sullivan, Senior Product Manager Windows Phone 7, confirmed exactly this. In a recent statement at CNet's Bey0nd B1nary blog, Sullivan said that Microsoft had to make some trade-offs and even Microsoft doesn't have unlimited resources. Therefore the Windows Phone 7 team had to prioritize doing fewer things really well. Since, for the worldwide market, the vast majority of phones are GSM phones, Microsoft focused on GSM first and then plan to deliver an update that will have great CDMA support in the first half of 2011.
For the worldwide market, this decision doesn't have any major impacts at all since - globally - GSM (TDMA) and 3GSM (WCDMA) are the systems of choice. However for the U.S. it means that first Windows Phone 7 devices can be expected to be available from AT&T Wireless and T-Mobile U.S. while Verizon Wireless and Sprint customers have to wait until anytime 2011 to get their hands on Microsoft's next mobile OS version.
Cheers ~ Arne