By registering a Nintendo Network ID to your Wii U or Nintendo 3DS you can enjoy a wide range of network services.
On Nintendo 3DS, a Nintendo Network ID is required to:
Post to Miiverse, our unique network communication service
Download free software, demos, and videos from Nintendo eShop
Please note: a Nintendo Network ID is not required to purchase paid downloadable content from Nintendo eShop on Nintendo 3DS.
On Wii U, a Nintendo Network ID is required to:
Play online games with other users
Access online services such as Miiverse, Wii U Chat, and more
Download content from Nintendo eShop