A communication system comprising: a data generation device that generates target data; a server that controls service contents usable with the data generation device; and an intermediary terminal that mediates a communication between the data generation device and the server, wherein the server includes a first transmission unit configured to transmit, to the intermediary terminal, service content information indicating a service content associated with device identification information identifying the data generation device received from the intermediary terminal, wherein the intermediary terminal includes an acquisition unit configured to acquire, from the data generation device, the device identification information identifying the data generation device, a second transmission unit configured to transmit the acquired device identification information to the server via a communication network, a reception unit configured to receive, from the first transmission unit of the server, the service content information; and a process execution unit (42, 43) configured to execute processing on the target data input from the data generation device in accordance with the service content indicated by the service content information, wherein the transmission unit transmits terminal identification information identifying the intermediary terminal to the server via the communication network, the reception unit receives an application, transmitted from the server based on the terminal identification information that the server has received, and the process execution unit (42, 43) executes the processing on the target data by activating the received application, wherein the data generation device is an image capturing device and the target data is image data, characterized in that the second transmission unit is configured to transmit image capturing device information received by the acquisition unit from the image capturing device to the server; wherein the first transmission unit is configured to transmit pre-registered service content information corresponding to the image capturing device information to the second transmission unit; wherein the process execution unit (42, 43) is configured to execute the processing on the image data in accordance with the pre-registered service content information a data generation device that generates target data; a server that controls service contents usable with the data generation device; and an intermediary terminal that mediates a communication between the data generation device and the server, wherein the server includes a first transmission unit configured to transmit, to the intermediary terminal, service content information indicating a service content associated with device identification information identifying the data generation device received from the intermediary terminal, wherein the intermediary terminal includes an acquisition unit configured to acquire, from the data generation device, the device identification information identifying the data generation device, a second transmission unit configured to transmit the acquired device identification information to the server via a communication network, a reception unit configured to receive, from the first transmission unit of the server, the service content information; and a process execution unit (42, 43) configured to execute processing on the target data input from the data generation device in accordance with the service content indicated by the service content information, wherein the transmission unit transmits terminal identification information identifying the intermediary terminal to the server via the communication network, the reception unit receives an application, transmitted from the server based on the terminal identification information that the server has received, and the process execution unit (42, 43) executes the processing on the target data by activating the received application, wherein the data generation device is an image capturing device and the target data is image data, characterized in that the second transmission unit is configured to transmit image capturing device information received by the acquisition unit from the image capturing device to the server; wherein the first transmission unit is configured to transmit pre-registered service content information corresponding to the image capturing device information to the second transmission unit; wherein the process execution unit (42, 43) is configured to execute the processing on the image data in accordance with the pre-registered service content information