A content handling device comprises a plurality of content transformation modules that can define one or more paths from a content source module to a content sink module. The content is associated with one or more usage rules requiring one or more transformations to be applied to the content. To enforce usage rules, each content transformation module is configured to receive the content, apply a transformation to the content in accordance with the usage rules and apply a tagging operation corresponding to the transformation to the content. In some embodiments output of the content by the content sink module is prevented if all tagging operations corresponding to the usage rules have not been applied. While in some embodiments usage rule tags corresponding to the usage rules are embedded locally at the content handling device, the disclosure also extends to a content distribution system with a usage rule tag embedding functionality.