1. An information extracting server comprising: a collecting unit configured to collect a text in which a keyword of interest indicating information of interest that a user is interested in appears, the keyword of interest, and a time of creation of the text; a keyword extracting unit configured to extract a keyword included in the text except for the keyword of interest, and the time of creation; a local hot word extracting unit configured to extract the keyword having a time score obtained on the basis of an appearance frequency of the keyword in a time interval, which is a period T1 backward from the time of creation, exceeding a first threshold value and a local score on the basis of the appearance frequency of the keyword in a local area indicating a range of a specific topic exceeding a second threshold value as a local hot word, and also extract the extracted time interval of the extracted keyword and the keyword of interest corresponding to the keyword; and a local hot word storing unit configured to store the extracted local hot word, the time interval, and the keyword of interest.
4. The information extracting server according to claim 1 , wherein the keywords of interest are classified into categories and are stored in a category storing unit, and the local hot word extracting unit tallies the extracted local hot words for each category by using the keywords of interest and the categories stored in the category storing unit.