US Patent 7233958 Communications in an item tracking system

System and methods for communicating tracking information about tagged items. A tagged item is a tangible item that carries a self-identifying tag. The tracking information can be stored in the tag or in a document that is accessible through an item tracking system. The tracking information can be accessible by multiple consumers having different levels of access. The methods include methods for masking redundancies in the tracking information, filtering the tracking information, and controlling access to the tracking information.