5. The method of claim 1 , wherein the calculating of the relation value comprises: calculating a first sub-relation value between the first inquiry search word and the answer candidate keywords based on a frequency of the answer candidate keywords being included in the search word history; calculating a second sub-relation value between the first inquiry search word and the answer candidate keywords based on a frequency of the answer candidate keywords being included in the webpage information; and calculating the relation value through linear combination of the first sub-relation value and the second sub-relation value.
1. A method of providing an answer keyword, by a device having a processor, to a user terminal, the method comprising: obtaining at least one of a search word history comprising a first inquiry search word of a certain domain pre-received from first user terminals, and webpage information selected by the first user terminals from a search result according to the search word history; extracting answer candidate keywords regarding the first inquiry search word from at least one of the search word history and the webpage information based on keyword lists of the certain domain; calculating a relation value between the first inquiry search word and each of the extracted answer candidate keywords; and when the first inquiry search word is received from a second user terminal, transmitting answer keywords for the first inquiry search word, which are selected from the answer candidate keywords based on the relation value, to the second user terminal.