The iPhone sees the forum as you do on your desktop. Its the same webkit engine safari and chrome use. But sometimes on a 3 inch screen you like a site to be optimized for touch for really quick access. mp3Car.com will automatically switch to the "mobile" style if you are using a WAP browser, but for smart phones that can display the full web it doesn't do anything. The option 'iphone' is there for you if you want to use it, I won't force anything.
Opera automatically re-arranges things when you zoom in to be a single column if you want. So it pretty much already does this. Rotate the phone 90degrees and the column is exactly as shown in the image. Has been for a while. Guess I am just not seeing the new part here unless it is just a workaround for iphone's...
I can't explain it, you have to use a web app to really understand it. The iPhone will zoom to a DIV when you tap on it and fill the screen just like opera. It doesn't really re-arrange it just fills the phone with the material you clicked on.
But I mean, a LOT of companies make web apps optimized for touch, and they make apps for the app store as well, so though you may not see the point, its obvious there is a reason for it.