A method for displaying usage histories of applications executed by devices (110; 120; 130; 140; 150; 160) arranged to communicate with each other over a network, the method comprising: storing usage histories of applications within a first device, that the first device has executed with a plurality of other devices through a network connection, the usage histories being stored in a plurality of tables, the plurality of tables comprising an application table listing applications that the first device 110 has executed through connection with the other devices, a device table 840 listing devices that can be connected to the first device on the network, a sequence table listing events and the sequence occurring when the first device 110 has executed corresponding applications with the other connected devices, and a job table storing job records of jobs executed by the first device with the other devices using the applications, each job record comprising a job ID, an event ID in the sequence table, a job name, and information regarding digital content; setting, in the first device, at least one of a first mode and a second mode for displaying part of the usage histories stored within the first device; when the first device is set in the first mode, sorting usage histories in the sequence table, with respect to device IDs, extracting application IDs corresponding to the device IDs, creating first partial usage histories of the executed applications arranged by device, with respect to the plurality of other devices, and displaying said first partial usage histories, and when the first device is set in the second mode, sorting usage histories in the sequence table with respect to application IDs, extracting device IDs corresponding to the application IDs, creating second partial usage histories of the plurality of other devices arranged by application, with respect to the executed applications, and displaying the second partial usage histories, and when one of the plurality of other devices is selected from the displayed first partial usage histories or one of the applications is selected from the displayed second partial usage histories, provide event IDs corresponding to the selected device or application from the sequence table to the job table, searching the job table to create detailed usage histories, using the event IDs, and displaying the detailed usage histories. storing usage histories of applications within a first device, that the first device has executed with a plurality of other devices through a network connection, the usage histories being stored in a plurality of tables, the plurality of tables comprising an application table listing applications that the first device 110 has executed through connection with the other devices, a device table 840 listing devices that can be connected to the first device on the network, a sequence table listing events and the sequence occurring when the first device 110 has executed corresponding applications with the other connected devices, and a job table storing job records of jobs executed by the first device with the other devices using the applications, each job record comprising a job ID, an event ID in the sequence table, a job name, and information regarding digital content; setting, in the first device, at least one of a first mode and a second mode for displaying part of the usage histories stored within the first device; when the first device is set in the first mode, sorting usage histories in the sequence table, with respect to device IDs, extracting application IDs corresponding to the device IDs, creating first partial usage histories of the executed applications arranged by device, with respect to the plurality of other devices, and displaying said first partial usage histories, and when the first device is set in the second mode, sorting usage histories in the sequence table with respect to application IDs, extracting device IDs corresponding to the application IDs, creating second partial usage histories of the plurality of other devices arranged by application, with respect to the executed applications, and displaying the second partial usage histories, and when one of the plurality of other devices is selected from the displayed first partial usage histories or one of the applications is selected from the displayed second partial usage histories, provide event IDs corresponding to the selected device or application from the sequence table to the job table, searching the job table to create detailed usage histories, using the event IDs, and displaying the detailed usage histories.