At the event, Iwata showed off how 3DS consoles can passively exchange data between each other in an automatic TagMode and how Mii customizable avatars will make their way onto the system.
The meat and potatoes of "Tekken Tag Tournament" is the tagmode that allows you to hit the shoulder button to call in another previously chosen fighter to help you defeat your opponents.
The Wi-Fi also will enable a "tag" mode that will let gamers share information from one console to another without needing to physically link the devices.