The developer has no plans to actually release this commercially, but the code exists and he's going to be putting it out on Codeplex for others to look at. The point, of course, was more conceptual: to make an app without an app. And in doing so he took advantage of Mango's new features for developers, including multi live tile + agents + deep link.
It's nice to see devs like Rudy pushing the boundaries of programming less than 24hrs after the release of the Mango SDK. It will be very interesting to see what devs come up with next!