User blog:Segatendo1985/About signing in

When launching Miiverse from the Nintendo 3DS Home Screen, you will have to sign in to your Nintendo Network ID in order to being using Miiverse. When asked, enter your password to continue. An incorrect password will require you to try again. If you have already selected to sign in automatically through the 3DS System Settings, you will not have to enter a password and you will be signed in automatically. This goes for all other online services on the 3DS. Depending on how good of a connection you have, the automatic login will be fast.