5. A method for conducting a weighted keyword search, the method comprising steps of: a computer displaying a graphical presentation showing respective keywords, in response to receiving a request for a weighted keyword search, the graphical presentation comprising respective nodes representing the respective keywords and lines connecting the respective nodes; the computer receiving a user interaction position on an area surrounded by the lines connecting the respective nodes; the computer determining respective weights of the respective keywords, based on proximity of the user interaction position to the respective keywords; the computer conducting the weighted keyword search of documents based on the keywords and the respective weights of the keywords; wherein the user interaction position is within a polygon formed by three or more lines connecting three or more nodes representing three or more keywords; and wherein a weight of a specific one of the three or more keywords is determined based on a ratio of a distance between the user interaction position and a specific one of the three or more nodes to a sum of distances between the user interaction position and each of the three or more nodes, wherein the specific one of the three or more nodes represents the specific one of the three or more keywords.
6. The method of claim 5 , wherein, for the weighted keyword search related to two keywords, the user interaction position is on a line connecting two nodes representing the two keywords.