6. An information processing apparatus comprising: an acquisition unit connectable to a server by way of a network and adapted to acquire one or more distributed keywords; a central processing unit adapted to determine an importance level of each keyword acquired by the acquisition unit, wherein, when the respective keyword is registered, the central processing unit calculates the importance level of the keyword by subtracting a time difference value from a number of occurrences of the respective keyword, in which the time difference value is equal to a predetermined value times a difference between a current time and a last acquisition time of the respective keyword, and wherein, when a result of subtracting the time difference value from the number of occurrences of the respective keyword is negative, the importance level of the respective keyword is set to zero, wherein, when the respective keyword is not registered, the central processing unit sets the importance level of the respective keyword to one; an extraction unit adapted to extract text information of a subtitle included in a program; a subtitle morphological analysis unit adapted to perform morphological analysis on the text information of the subtitle; and a comparison unit adapted to compare each keyword acquired by the acquisition unit with each keyword detected via the morphological analysis performed by the subtitle morphological analysis unit.
6. An information processing apparatus comprising: an acquisition unit connectable to a server by way of a network and adapted to acquire one or more distributed keywords; a central processing unit adapted to determine an importance level of each keyword acquired by the acquisition unit, wherein, when the respective keyword is registered, the central processing unit calculates the importance level of the keyword by subtracting a time difference value from a number of occurrences of the respective keyword, in which the time difference value is equal to a predetermined value times a difference between a current time and a last acquisition time of the respective keyword, and wherein, when a result of subtracting the time difference value from the number of occurrences of the respective keyword is negative, the importance level of the respective keyword is set to zero, wherein, when the respective keyword is not registered, the central processing unit sets the importance level of the respective keyword to one; an extraction unit adapted to extract text information of a subtitle included in a program; a subtitle morphological analysis unit adapted to perform morphological analysis on the text information of the subtitle; and a comparison unit adapted to compare each keyword acquired by the acquisition unit with each keyword detected via the morphological analysis performed by the subtitle morphological analysis unit. 10. The information processing apparatus according to claim 6 , in which the predetermined value is 0.5.