A method, system and device for sharing rights adapted to be associated with items, the method and system including generating at least one of usage rights and meta-rights for the items; defining, via the usage rights, a manner of use for the items; and defining, via the meta-rights, a manner of rights...http://www.google.com.hk/patents/US8001053?utm_source=gb-gplus-share專利 US8001053 - System and method for rights offering and granting using shared state variables
