I signed up for my Windows Mobile Marketplace account while I was at MIX 2010. I was somewhat disappointed that after I shelled out the $99 for the first year, my Windows Phone 7 Series applications can't be uploaded until sometime in the summer of 2010. I don't have any real interest in writing Windows Mobile 6.5 applications, to be honest. I'm only concerned with writing for the Windows Phone 7 Series because: