Abstract: A communication terminal sends an access request to a WWW server connected to a network to a relay server in the network. The relay server sends this access request to the WWW server and receives display data from the WWW server and sends an advertisement ID specifying an advertisement satisfying a predefined condition to the communication terminal together with the display data. The communication terminal displays a screen by this display data and sends an advertisement data request including an advertisement ID received from the relay server through the relay server to an advertisement distribution server. When receiving an advertisement data request, the advertisement distribution server sends the advertisement ID contained in the advertisement data request to the communication terminal through the relay server. When receiving the advertisement data, the communication terminal displays an advertisement corresponding to the advertisement data along with the screen corresponding to the display data.

Abstract: A credit card transaction system that is used for contracts for various electronic-commerce services comprises a mobile station 100, a mobile telephone network 20, a mobile packet communication network 30, a CAT 40a, 40b, . . . , a CAFIS network 50, a credit card company's server 60A, 60B, . . . , and the Internet 70. A request from the mobile station 100 for a credit card contract is transmitted to any one of the credit card company's server 60A, 60B, . . . through a gateway server 32; in a case where the contract is approved, credit card contract information is transmitted from any one of credit card company's server 60A, 60B, . . . to the mobile station 100 through the gateway server 32, the credit card contract information being stored in the mobile station 100.