1. A method of tracking the usage of at least one digital content comprising: preparing the content in an encoded format, the content including a unique content ID in a header of the content; distributing the content to a user computer system; receiving at least one usage tracking message from the user computer system in response to the usage of the content by the user computer system, the usage tracking message including an identifier based on the unique content ID and an anonymous copy ID; and verifying the usage tracking message.