An apparatus transfers the title of content to an ID-assigning unit which assigns an ID to the content and transmits the content ID to a broadcasting unit via a tagging unit. A broadcasting apparatus then broadcasts the content ID and a receiver extracts the content ID from a received signal and transfers the content ID to a verification unit which determines whether or not the content ID received from a reception functional unit matches a stored content ID. If the content ID received from the reception unit matches a stored content ID, user information of the receiver is transmitted to a privacy-guarding unit. The privacy-guarding unit searches privacy-guarding items and, in accordance with a result of the search, only necessary user information presented by the verification unit is transmitted to a provider unit.