22. The method of claim 18 , further comprising: after the input for displaying the first chat message is received in response to the notification that the first chat message has been received, displaying a pop-up window over the messenger chat window if the second chat message is not currently displayed in the message chat window, wherein the pop-up window includes the first chat message and the second chat message.
23. The method of claim 22 wherein, if an input for displaying the messenger chat window is received while displaying the first chat message and the second chat message in the pop-up window, the method further comprising: moving the second chat message to be displayed in the messenger chat window, and displaying the first chat message and the second chat message in the message chat window.