Data processing apparatus, data processing method, data processing system, storage medium and program

A method of processing a list of content data items, said method comprising steps of:

• wirelessly detecting, by a content data item device storing content data items, a plurality of portable terminal devices when the plurality of portable terminal devices are in a communicable area of said content data item device;
• defining, by the content data item device, a maximum number of hops from the content data item device to another portable terminal device outside the communicable area;
• receiving, by the content data item device, from one of said plurality of portable terminal devices in the communicable area, a list representing content data items stored on the one portable terminal device and on at least one other portable terminal device outside the communicable area, a number of hops from the content data item device to the at least one other portable terminal device not exceeding the defined maximum number of hops, said list comprising a representation of at least one content data item indicated on the list as being recommended by a user of the one portable terminal device or by a user of the at least one other portable terminal device, wherein each at least one content item is indicated as being recommended based at least in part on one or both of (1) being reproduced by the one portable terminal device or by the at least one other portable terminal device for at least a predetermined time period and (2) being designated as a favorite of a user of the one portable terminal device or of the at least one other portable terminal device;
• identifying a content data item indicated as being recommended in a list received from one of the plurality of portable terminal devices which is not stored on the content data item device;
• for each content data item indicated as being recommended on a list received from one of the plurality of portable terminal devices, determining a number of lists on which the content data item is indicated as being recommended;
• and
• identifying a content data item indicated as being recommended on a greatest number of lists received from said plurality of portable terminal devices.