Miitomo is now one year old in various territories, including the US and some European countries - it actually hit the landmark in Japan on 17th March. It's a notable anniversary, as it was the first mobile app to come out of the partnership between Nintendo and DeNA.
As a concept it was always rather intriguing, as it's a social app that is controlled in order to be 'safe' - initially it was primarily about answering set questions and sharing those answers with those on your friend list. After a quick start the app lost a fair bit of momentum, however - it didn't keep a sizeable audience engaged for long, and its revenues have never been much for Nintendo to boast about. It's actually evolved and improved a fair deal through updates over the past year, though many likely haven't been aware.
In any case, 31st March is the one year anniversary in some countries, and Nintendo is running a whole lot of giveaways, promotions and limited period Miitomo Coin gear. There's even a contest to design clothing that'll appear in the app.
As the official website shows, there's a lot going on over the next 10 days or so.
We suspect many left Miitomo behind quite some time ago, but if you're still dipping into the app let us know in the comments.