1. A content delivery system comprising: a content server connected to a network; a gatekeeping apparatus connected to said network; and a user terminal for transmitting to the gatekeeping apparatus a first message containing a request for content from the network and a second message to said content server for requesting the content therefrom, wherein said gatekeeping apparatus is responsive to said first message for making a comparison between policy data of said content server and preference data of said user terminal and making a decision as to whether or not the content can be retrieved from said content server and performing control on the transmission of said second message according to said decision, wherein said policy data and said preference data include information as to precision of parameter data for use by the content server to generate said content, wherein said user terminal includes: a cache memory; and control circuitry for (a) making a search through said cache memory for detecting an indication of decision using an indicator of said content as a key prior to the transmission of said first message to the gatekeeping apparatus, (b) if said search fails, transmitting said first message to said gatekeeping apparatus and mapping an indication of said decision of said gatekeeping apparatus to the indicator of said content in said cache memory, and (c) if said search succeeds, acquiring said parameter data if the decision indication in said cache memory indicates that said content can be retrieved.