For those who don't know, the "Pad Only" area simply houses apps that are tagged as pad-only by users -- you can do so by tapping and holding an app icon in the drawer, followed by dragging it to the "Add Pad-only Tag" button in the top-right corner.
In a symbiotic program that should potentially benefit studios, consumers, and perhaps even the medium itself, Apple hooked up with HD Radio developer iBiquity to integrate a "Tag" button into future hardware releases, which when triggered loads metadata about the current song to memory for future transfer to a docked iPod.
The meat and potatoes of "Tekken Tag Tournament" is the tag mode that allows you to hit the shoulder button to call in another previously chosen fighter to help you defeat your opponents.