Is UserExtendedProperties.GetValue user-specific or device-specific?

I'd like to use UserExtendedProperties.GetValue to associate a user with a high score table in a game I'm working on. Reading Microsoft's own API description I cannot work out whether this applies to a user (blah@live.com)开发者_运维知识库 or a physical device. Does anyone know?

Chris

UserExtendedProperties.GetValue("ANID") is an anonymous ID based on the user's Live ID. So, the same Live ID logged in from multiple WP7 devices will have the same ANID.