17. The system of claim 16 , wherein the associated score calculation module is configured to calculate a single keyword associated score by applying an individual weight to the association indicator.
17. The system of claim 16 , wherein the associated score calculation module is configured to calculate a single keyword associated score by applying an individual weight to the association indicator. 18. The system of claim 17 , wherein the associated score calculation module is configured to calculate a plural keyword associated score based on the single keyword associated score, and the plural keyword associated score corresponds to a score calculated by numerically expressing an association between the associated keyword or the extended keyword and the other keywords.