A system and method applied to a communications network which transmits document portions in which an original document portion having an identifier portion and an information portion is replaced or swapped with a substitute document portion. The system has a controller, typically a proxy server, for reading the identifier portion of the original document portion, determining the information portion of the original document portion, and issuing a swap order when an undesired original document portion is found. A substitute document server receives the swap order and sends the substitute document portion to the controller. A swapping device or mechanism inserts the substitute document portion in place of the original document portion and the substitute document portion is passed on to the user set and displayed. The controller and swapping mechanism can be integrated with the user set or with the resources of the service provider and their functionality can reside in software.