Abstract: There is provided a messenger service system capable of realizing a messenger service in which position information of a user is automatically opened and a burden of care is reduced. The messenger service system includes communication terminals, a messenger server and a database. The area data sets are stored in association with identification data in the database. Each data set includes predetermined area definition data and notation data. If position data and identification data are received from a communication terminal, the server searches for an area data set associated with identification data. If the area data set including a position to be represented by received position data is detected, the server transmits notation data in the area data set to other communication terminals. The communication terminals receive data and display. Thus, the user of a second communication terminal can grasp a position of a first communication terminal.