A method for outputting a message using a game result information window. The method includes: dynamically determining, by a computer system, the size of an area for displaying additional information on a first user in a game result display window and whether to display the additional information, using the result of a game played by the first user; and extracting the additional information on the first user, reflecting the same in game result display window data, and transmitting the game result display window data to a second user terminal so as to display the game result display window data in the game result display window. When it is determined that the additional information on the first user is displayed, the retrieved additional information on the first user is displayed in the area for displaying the additional information on the first user in the game result display window.