If you read the Who Killed The Kin article linked at the bottom of that one you'll see that a large part of it was because Verizon renegged on their original promise to offer these phones at a cheap subscription rate which would help in drawing in the tweens and twentysomethings these phones were aimed at. Instead they were priced the same as much more fully featured smartphones.
It's a shame, I think the UI and cloud integration on these phones is extremely well done. I hope they decide to integrate this tech into the Win7 phones.







