How the hell does mii plaza work? You can send people items for their miis? I'm so confused about the friend system on 3ds despite having one for a year.
The Mii Plaza shows all streetpassed Miis as well as the ones you've met playing online. You can further customize your Mii if you play Find Mii and Find Mii 2, which is an RPG-like game where you get all sorts of hats after defeating certain enemies. You can play Find Mii with either streetpassed Miis or dog and cat warriors that you hire using Play Coins (that you earn by walking around with your 3DS). The other thing you can do is collect puzzle pieces for cute little 3D dioramas on Puzzle Swap. To earn pieces you can either buy them or have a streetpassed Mii give you one.