A data communication control system, a communication system, a service providing method, and a computer program which provide a service such as a game performed by changing the number of points used as a gamble point, from a game server using a web server computer to a user terminal and issue a code string used as a keyword via various media such as the Internet, various shops, journals, the TV broadcast, and the radio broadcast, so that a user who has acquired the issued code string transmits the code string from the user terminal to a game server and the game server assigns a point necessary for providing the service to the user according to the received code string.