Xbox Live
From PinataIsland.info, the Viva Piñata wiki
Xbox Live is a subscription-based online gaming service for Microsoft's Xbox and Xbox 360 video game consoles.
In Viva Piñata it will be possible to exchange and send Pinata as tourists, to and from other player's gardens and they can then interact with that person's game and Piñata. They'll feature a tag which shows that that particular pinata is from your garden. This is enhanced by the ability to customise any of your Piñata with items and accessories acquired from the Xbox Live Marketplace.