A user device receives the content, and pays a content fee, based on the usage control policy of the content, by electronic money up to the allowable amount of money set in an issue log. The user device then creates a usage log including a content identifier and sends it to a service provider. The service...http://www.google.co.uk/patents/US20010053223?utm_source=gb-gplus-sharePatent US20010053223 - Content transaction system and method, and program providing medium therefor
