PC World posted an article on the Windows Phone 7 SD card problem

I am by no means a fan of Windows Phone 7, and I don't see a coherent mobile strategy at Micosoft. But the current brouhaha over Windows Phone 7 devices reformatting MicroSD cards into a proprietary format is misguided. This is not some boneheaded Microsoft move. Microsoft has been very clear on the matter for months: Windows Phone 7 doesn't support removable media cards.

Microsoft decided some time ago -- and has been forthright about this for months -- that the device would be like Apple's iPhone in that its storage would be closed, not like BlackBerry or Android devices.

  Windows Phone 7's SD Card Problem: Not Microsoft's Fault