9. The apparatus of claim 4 , wherein the third detector comprises: an association word searcher configured to searching association words of the target topic; an association word based topic template searcher configured to searching association words and related topics based on the search results of the association word searcher; a target topic based filter configured to removing topics that are not related to the target topic from among the search results of the association word based topic template searcher; a topic ranker configured to measuring degrees of being issues for topics left after being filtered by the target topic based filter to rank the topics by date; and a related topic presenter configured to provide topics that become issues through a user interface based on ranking results by date that are obtained by the topic ranker.
9. The apparatus of claim 4 , wherein the third detector comprises: an association word searcher configured to searching association words of the target topic; an association word based topic template searcher configured to searching association words and related topics based on the search results of the association word searcher; a target topic based filter configured to removing topics that are not related to the target topic from among the search results of the association word based topic template searcher; a topic ranker configured to measuring degrees of being issues for topics left after being filtered by the target topic based filter to rank the topics by date; and a related topic presenter configured to provide topics that become issues through a user interface based on ranking results by date that are obtained by the topic ranker. 10. The apparatus of claim 9 , wherein the target topic based filter removes topics that are not related to the target topic based on the association word and the property values of the topic templates.