As Conrad Zimmerman told us earlier tonight, the 3DS has a data exchange feature called "Tag Mode." This mode allows for the 3DS system to exchange data with others or download files from wifi hotspots all while the system is asleep.
Street Fighter IV 3D Edition takes full advantage of this ability and it's all detailed in the above video. I can't understand a thing, but the basic point is that stuff happens without you even knowing about it. A cool way to keep your rank up, I suppose.