The new Viva Piñata game on the Xbox 360 uses the Xbox Live Vision camera to read codes found on Viva Piñata cards, unlocking new piñatas. It's an impractical feature (if only there were some other way to enter short text strings into a game ...) but it's a fun gimmick. And it's designed such that the camera can read card images not just from physical cards, but from screens on computers and portable devices, which enhances the possibilities for sharing.
The DS has a Viva Piñata game (Pocket Paradise). The DS has screens. Wouldn't it be awesome if you could use the DS game to send stuff to the 360 game? It would be -- and is! Rare had it implemented, according to MTV Multiplayer's interview with Rare's Justin Cook, but too late. "We got it to work, but it was too late in the development cycle," Cook said. "It's one of those things where you just kick yourself." A strange statement coming from Rare. Can't they just delay the game for a couple of years?