You know those pesky Friend Codes that Nintendo had? Well sometime in the near future no one will remember them anymore as Nintendo has confirmed that they will be replacing the current system with a "more user-friendly Account ID system" for the Wii U. This Account ID system will be linked with your Nintendo Network ID.
I remember playing Yugioh on the nintendo DS and having to go online and ask random people for a friend code just to be able to duel them. I think this will be a nice change for those few who enjoy Nintendo Wi-Fi.