A 3DS system update has been released which introduces Miiverse functionality and the ability to register a Nintendo Network ID on the console.
Once installed, 3DS users will be able to create a Nintendo Network ID on their handheld or link an existing account, combining their Nintendo eShop balances and wish lists from Wii U.
Miiverse support also allows 3DS users to connect with players around the world, sharing their experiences with other 3DS users. Posts to the Miiverse can include a screen shot from either the top or bottom screen of the 3DS.
The update also removes the limit on the number of times a user can transfer their content to a different 3DS system.
Source: Press release