Open Safari in full screen on an iPhone or iPod Touch
The small screens of an iPhone or iPod Touch can make viewing desktop-oriented websites a bit difficult. Sure, you can zoom, but that navigating a page bit by bit has its own issues. In iOS 6, when you view a website in horizontal orientation on these devices, you now get a Full Screen button that gives you a few more pixels for seeing the page (the menu bar disappears).
How much do you want to bet that the "iPad Mini" will have this feature, too?