https://twitter.com/serkantoto

The tweet says " About that first Nintendo-DeNa mobile game: Expect the unexpected, and soon"

Probably next week then I would guess?

Awesome! It's about time! I wonder what it will be? : D Hopefully something good.

Could this mean we're getting a new Direct soon? I really hope so.

They'll probably have a real event for the mobile game as in a press briefing, not a Direct.

Direct's are for Nintendo fans, Nintendo's mobile games are meant to attract non-Nintendo fans who wouldn't watch Direct in a million years.

Everything Nintendo+Mobile makes me tense up. Hopefully it goes well, but well enough that that becomes a major focus

Anyways, I use Windows Phone, so I'm 100% sure I'll never get to play whatever game this is =P

If it means the series may come back with a 3DS version and/or the NX gets it with the option of physical controls ... yes please. 

I have a feeling it may be a Mario Kart game since the leader of the mobile games also directed the Mario Kart series.
The controls (although clunky) would be relatively simple as well:
Tilt to steer
A and B on screen to accelerate or break
And Z to use items.

Would be amazing if it had a drift button but most mobile users wouldn't care.

Finally. I already have my guess on what it will be. I wonder what franchise they'll choose.