Setting up a user account will be one of the first things to do when starting up the system, and it'll be followed by a Nintendo Network ID; it's the ID that will drive interactions on Miiverse, eShop purchases and Wii U Chat. Perhaps most importantly, eShop purchases on the ID will be accessible by all user accounts on the system, so buying a game while logged in on one account won't stop others jumping into their own user settings and playing the same game.
The Nintendo Network ID is intended to work across all Nintendo platforms in future — we imagine a 3DS update will introduce it in good time — and as suggested before it'll also work on related services on computers and smartphones. That'll open the door for Miiverse via various browsers, or potentially managing eShop purchases while away from Wii U or 3DS.
So, 12 user accounts and Nintendo Network ID download purchases that can be played across them all: are you pleased with this announcement? You can also check out the translated video, below.