WP7 was launched in U.S. for more then 1 year before Nokia entered this platform. Yet it only managed less than 2% penetration. As for Nokia, its brand name in the U.S. is junk. It is associated with cheap flip phones that grandmas use. So where does your confidence that WP and Nokia will succeed in U.S. comes from? This is a marriage between a rejected os and a junk brand name.