Nintendo
The Wall Street Journal liveblogged the investor meeting in Japan where Nintendo president Tatsumi Kimishima announced "Miitomo." Kimishima reportedly described the game as, " free-to-play, with attractive add-ons that people can pay for," while the WSJ paraphrased his description as such: "In the new 'Miitomo' game, users will design their own avatars, or 'Miis,' to communicate with other users."
This is what "Miitomo" looks like:
Nintendo
Miis have existed as part of Nintendo's online experience for years now, since the Wii era. "Miitomo" sounds like a variation of a service that already exists on Nintendo's 3DS handheld console, where your Mii can virtually visit other people's 3DSes by simply walking past them in real life. It looks like "Miitomo" may function in a similar way.
Connecting the smartphone side of Nintendo to its console side is a new service named "Nintendo Account." Like Microsoft's Xbox Live service and PlayStation's Plus service, Nintendo Account is cloud-based and serves to unify your various Nintendo devices across a single account.
Still confused? Think of it like your Google login, but for everything Nintendo.
For those expecting a "Super Mario" or "Pokémon" game, it looks like you'll have to play the waiting game instead. There are another five games expected from Nintendo's smartphone partnership with Japanese mobile game developer DeNA before March 2017, so there's still a strong likelihood Nintendo will bring some of its most prominent properties that way in some form or another.
And for those worried about Nintendo losing focus on console gaming, Nintendo's creative director (and "guy who created 'Super Mario'") Shigeru Miyamoto reportedly reassured attendees that DeNA is overseeing mobile, "while Nintendo will focus on ways to guide users to its hardware." Nintendo will release more information on its next console (only known by a codename, "NX") at some point in 2016.