A device for transmitting an answer message, comprising: a display configured to display information; a communicator configured to receive a question message from another device; a processor configured to analyze the question message and to control the display to display graphics representing a plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) which are includable in an answer message for the received question message and relations between the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017), wherein the graphics representing the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) are indicated by nodes and the graphics representing the relations between the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) have a tree structure or a radial structure with at least two levels; and a user input unit configured to receive a user input that selects at least one of the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017), wherein the processor is further configured to, when the at least one of the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) is selected by the user, generate an answer message including the selected recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) and other recommendation information linked to the selected recommendation information according to the displayed graphics, wherein the communicator is further configured to transmit the generated answer message including the selected recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) to the another device according to the user input, wherein the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) are connected to one another based on weight values regarding at least one attribute among preference, importance, location, time and atmosphere of the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017). a display configured to display information; a communicator configured to receive a question message from another device; a processor configured to analyze the question message and to control the display to display graphics representing a plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) which are includable in an answer message for the received question message and relations between the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017), wherein the graphics representing the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) are indicated by nodes and the graphics representing the relations between the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) have a tree structure or a radial structure with at least two levels; and a user input unit configured to receive a user input that selects at least one of the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017), wherein the processor is further configured to, when the at least one of the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) is selected by the user, generate an answer message including the selected recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) and other recommendation information linked to the selected recommendation information according to the displayed graphics, wherein the communicator is further configured to transmit the generated answer message including the selected recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) to the another device according to the user input, wherein the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017) are connected to one another based on weight values regarding at least one attribute among preference, importance, location, time and atmosphere of the plurality of pieces of recommendation information (101-106, 1202, 1302, 1931-1935, 2011-2017).