Nintendo revealed more about Mario Kart 7's online, StreetPass and SpotPass options at the Nintendo 3DS Conference which is taking place in Japan now.
As you may already know, Mario Kart 7 will support 8-player online and, most importantly, it will run at 60 frames per second.
It has also been revealed that the game will have a Mario kart 7 channel which collects data from StreetPass, including the ghost Miis of players you pass in the street.
You can also select a player's data from the Mario Kart Channel and then race against them online.
As for SpotPass, there will be daily download ghost data.
Mario Kart 7 producer Hideki Konno is very keen on community features that Nintendo have created for Mario Kart 7. You can even create them yourself.