Windows Phone 7 follows the iPhone model of multitasking. The article here sounds very much like the reasoning behind the iPhone's implementation. Personally, I think they both have it wrong, and multitasking should be implemented but in a different way. Android is closer, IMO.

Now watch, iPhone 4.0 will include full preemptive multitasking and blow the doors off of WP7.. :-)

They also mentioned no copy/cut/paste. THAT is a huge mistake. Hopefully it won't take them two years to add the feature like it did Apple.