We're all very happy that Nintendo replaced the dreaded friend codes with the Nintendo Network ID on Wii U, but the system isn't without its faults. One major issue we have with it is the fact that our newly created Nintendo Network IDs are locked to a single Wii U console.
That's right, even though the major first-party games released with the console at launch – "Nintendo Land" and "New Super Mario Bros. U" – are pushing local co-op in a big way, playing at a friend's house, on their console, under your Nintendo Network ID, is out of the question.
According to an official post on the Nintendo Support site, it is currently impossible to sign into your account on a friend's console or transfer it to a new Wii U console if yours happens to break, brick or otherwise become a shiny paperweight.
"A Nintendo Network Account can only be used on the console where it was created," the page reads. "In the future, you will be able to use your Nintendo Network Account with future Nintendo consoles and other devices, such as PC's."
The post implies that you will be able to transfer it to other hardware in the future, but doesn't specifically state that you'll be able to sign in on your friend's console to track game progress, etc. I guess we'll have to wait and see what changes are made in the future.