A method for automatically changing information originating from at least either of a first user and a second user by using a mobile device includes steps of: (a) a first device searching second devices as a target to perform interaction and then selecting a specific second device among the searched second device to change the user-originating information; (b) the first device transmitting to, or receiving from, the specific second device data related to the interaction, if a touch gesture is detected in the first device; and (c) at least either of the first and the second devices allowing a server to update the information originating from at least either of the first user and the second user by referring to the transmitted data related to the specific interaction.