Miitomo is a social app inspired by the Tomodachi Life (known in Japan as Tomodachi Collection) games for Nintendo DS and 3DS. You create a Mii, dress them up and then pick their personality and voice. Nintendo will then ask questions about, well, almost anything, such as your favourite food or what you last bought. The idea is to write some witty or insightful responses, as they'll later appear in your friends' feeds. Likewise, your peers' comments will gather in your own Miitomo account, encouraging pithy replies and bizarre, possibly heartwarming conversations.

Then there's Miifoto, a separate feature that lets you poke your Mii into different poses and take pictures in front of colorful backgrounds. These can be shared on Twitter, Facebook, Instagram and Line -- an addictive mechanism that encourages sharing and Mii customisation.

It's a unique game and one that feels very Nintendo-like. How it will perform over a longer period of time, and in markets outside of Japan, remains a mystery however. The early signs are positive though -- 1 million downloads is impressive for any developer these days, especially those fighting for attention in the App Store or Google Play. If Nintendo can monetize Miitomo effectively (how many people will pay for a Splatoon-themed inkling outfit?) the app could grow into a nice little earner.