Your Mii Channel holds a terriblesecret: DS connectivity. We may not have the DS Personal Trainer: Walking (Aruite Wakaru Seikatsu Rhythm DS) yet, but our Wiis are apparently ready to connect to it. As this video demonstrates, you can unlock the DS connection feature in your own Mii Channel right now, by pressing A, B, 1, and then holding 2. The Wii will start looking for DS systems nearby capable of interfacing with the Mii Channel -- which pretty much means Personal Trainer, into which Miis can be imported. Even if the connection fails, your Mii Channel will now feature a "connect to DS" button.
Sure, this may be useless, but it's like a cheat code -- for your system! How very cool. Has this always been there, or did it sneak in with the last update?
[Update: Apparently the feature's been there since last year, or maybe before, but the method had yet to be documented.]