doesn't the iphone has an app to decode qr-codes similar to the one built into almost all keitai here in japan.
Yep. Called iMatrix. (There are probably others too)
Yes, that's one of the apps. Anyway, as you can see this is just one example that a URL may not look prima facie like a construct based on a FQDN. One issue on the UI side is that even with all the progress in graphics and visual representation for many things, to enter a URL we are still using a TTY interface. There are folks (MSFT is investing a bunch of money on it) doing R&D for touch sensitive data entry devices/UI that are context aware. You have now a little taste of that technology with the iphone and all the new smartphones and other gadgets that implemented the same idea. How many URLs you type to get to YouTube on the iphone/itouch ? ... none. The DNS (or whatever name we call it in the future) is not going away, it will go back to be what it was intented, and not just a giant global billboard where folks are fighting for space on it and where some other folks -even if they don't need it- buy space hoping that someday somebody will want their space at any cost making her/him rich. Cheers Jorge