To get started, you'll first need to create a Nintendo Account – the company's new multi-platform account system – by using an existing Nintendo Network ID, Facebook, Google+ or Twitter account or by creating a standalone account.
There's not much that can be done with a Nintendo Account just yet although pre-registering for Miitomo will score you some Platinum Points (virtual money) that can be used when Nintendo's new reward service launches alongside Miitomo.
Nintendo provided details about Miitomo late last year, the first of five mobile titles we can expect between now and March 2017. Developed in collaboration with DeNA, Miitomo is more of a social networking app than a true game as it allows users to create Mii avatars which then interact with others in the Nintendo universe.
Miitomo will utilize the free-to-play model meaning it'll offer in-app purchases for things like outfits for Mii characters and so on.
Interestingly enough, Nintendo's first mobile app doesn't lean on iconic characters like Mario or Link. That may be a mistake according to some but in the same respect, Nintendo may simply be playing it safe on its first outing. If we don't see the usual cast of characters by the second or even the third title, then yeah, there's probably reason for concern.
Miitomo is expected to arrive next month for Android and iOS devices.