10. A keyword display method according to claim 9 , wherein said emphasized display of the relevancy between the keywords is carried out by employing one of a thickness of a line indicative of the relevancy between the keywords, a distance between displaying positions of the keywords, and a color of a line indicative of the relevancy between the keywords, or a combination thereof.
12. A keyword display method according to claim 10 , said keyword display method displaying the distance between the displaying positions of the keywords in such a manner that it becomes shorter as said keyword relation degree becomes larger.