Is it regular maintenance, or something special?
http://www.nintendoworldreport.com/news/32696
The Wii U eShop is currently offline and undergoing maintenance.
The reason behind the service's downtime is unknown, but it may have something to do with tomorrow's Nintendo Direct presentation. This is just speculation, seeing how the maintenance may just be regular upkeep of the service.
Stay tuned to Nintendo World Report as we look into the situation.
Perhaps related to TVii since it's supposed to come out this month? Just wishful thinking on my part: every time I have to switch over from Netflix to Hulu, I remember how much I can't wait for TVii.