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Really cool! It doesn't work on WP7 though (which doesn't matter too much, because most people don't have a WP7 device)

It should work on Mango.

Haven't upgraded yet - will do it now!

Yes, works great on Mango. Like others mentioned, please do add the back button :)

Personally, I would prefer if comments were directly a link. Not a big fan of the popup.