Nintendo revealed this to veteran Japanese gaming mag Famitsu, which was quoted on the NeoGAF forum as saying, "In addition, the feature region lock the region can play the Wii U is limited is mounted, you can not play other than software that is sold in the area." (Thanks to Google for the seamless translation.) The news was later confirmed by CVG.
The main problem here is that the dedicated and culturally curious gamer who looks to import rare, quirky games from around the globe will be unable to do so. With Nintendo being a quintessentially Japanese company, many of the most popular games in its home country -- often completely baffling to Western gamers, but with their own specific charms -- are not released elsewhere.
Another issue is that those keen enough to get hold of a game early, because it's released in the US before Europe, for example, won't have this luxury either.
This will not seem like a big deal for most people, but some will be annoyed at the situation. This will likely lead to hacks or modding of the Wii U, obviously at the expense of invalidating the warranty, in order to find a way around this international restriction.
Nintendo's main competitors, Microsoft and Sony, allow publishers themselves to decide whether or not to use region locking on games for the Xbox 360 and PlayStation 3. As a result, almost all PlayStation titles are sold without such a lock -- thank you America for my Uncharted: Drake's Fortune copy one month early, all those years ago.
In comparison, Xbox 360 titles vary widely on whether there is a lock or not.
What do you think of the region-locking of the Wii U? Are you one of the hardcore few, livid at the fact that you won't be able to play the rarest of titles? Blow off steam down in the comments or over on our cosmopolitan Facebook page.