In one aspect a communication system is provided. A terminal generates predetermined music information on a reproduced piece of music and reproduction frequency information including a reproduction count of the piece of music. The terminal transmits the reproduction frequency information and its own apparatus ID to a server. The server computes a similarity coefficient between pieces of music reproduced by the terminal and another terminal on the basis of the terminals' reproduction frequency information and apparatus IDs. The server catalogs the computed similarity coefficient on a favorite list by associating the similarity coefficient with the reproduction frequency information and the apparatus IDs. The server identifies a similar piece of music reproduced by the terminal and the other terminal by referring to the favorite list and selects a piece of music reproduced by the other terminal but not reproduced by the terminal.