When I first heard about this I was confused because I was under the impression that ModNation Racers was supposed to be Sony's LittleBigPlanet of kart racing. I'm guessing that didn't turn out as planned and that's why this exists. Not that it's a bad thing.
LittleBigPlanet Karting looks to bring the hilarity and craziness of kart racers along with the customization and creation that the LittleBigPlanet series is known for. Hey, it's got rocket launchers so I'm down.