An electronic device comprising: a communication module; a memory configured to store messages received or transmitted by the communication module; a touch screen configured to display the received or transmitted messages; and a processor coupled to the memory, the touch screen, and the communication module, the processor configured to: obtain, via the communication module, a first message through a first message application, the first message being received and/or transmitted with first contact information of an interlocutor, obtain, via the communication module, a second message through a second message application, the second message being received and/or transmitted with second contact information of the interlocutor, control the touch screen to display the obtained first message and the obtained second message on a combined message display window of the interlocutor, by executing the first message application, determine if the interlocutor is in an available state or an unavailable state in the first message application, if the interlocutor is in the available state, send a third message to the interlocutor via the first message application; and if the interlocutor is in the unavailable state, control the touch screen to display a message recommending that the third message be transmitted to the interlocutor via the second message application; wherein the first message application and the second message application have different message reception and transmission techniques; and wherein the interlocutor is determined to be in the unavailable state if information indicating that the interlocutor is in an off state is received from a server. a communication module; a memory configured to store messages received or transmitted by the communication module; a touch screen configured to display the received or transmitted messages; and a processor coupled to the memory, the touch screen, and the communication module, the processor configured to: obtain, via the communication module, a first message through a first message application, the first message being received and/or transmitted with first contact information of an interlocutor, obtain, via the communication module, a second message through a second message application, the second message being received and/or transmitted with second contact information of the interlocutor, control the touch screen to display the obtained first message and the obtained second message on a combined message display window of the interlocutor, by executing the first message application, determine if the interlocutor is in an available state or an unavailable state in the first message application, if the interlocutor is in the available state, send a third message to the interlocutor via the first message application; and if the interlocutor is in the unavailable state, control the touch screen to display a message recommending that the third message be transmitted to the interlocutor via the second message application; wherein the first message application and the second message application have different message reception and transmission techniques; and wherein the interlocutor is determined to be in the unavailable state if information indicating that the interlocutor is in an off state is received from a server. obtain, via the communication module, a first message through a first message application, the first message being received and/or transmitted with first contact information of an interlocutor, obtain, via the communication module, a second message through a second message application, the second message being received and/or transmitted with second contact information of the interlocutor, control the touch screen to display the obtained first message and the obtained second message on a combined message display window of the interlocutor, by executing the first message application, determine if the interlocutor is in an available state or an unavailable state in the first message application, if the interlocutor is in the available state, send a third message to the interlocutor via the first message application; and if the interlocutor is in the unavailable state, control the touch screen to display a message recommending that the third message be transmitted to the interlocutor via the second message application; wherein the first message application and the second message application have different message reception and transmission techniques; and wherein the interlocutor is determined to be in the unavailable state if information indicating that the interlocutor is in an off state is received from a server.