Patent ID: 7266546

Claim:
An intermediate server, comprising: a providing unit that searches information in a central server based on a search request from a user on behalf of a user terminal and provides a search result to the user; a retaining unit that retains the search result as a user search history being connected with the search request to specialize in a field of information based on the user's interest; an index management unit that generates an index information in the specialized field of information for searching the information in the central server; and a storing unit that stores the index information, wherein the user search history is shared with a plurality of users and is used for supporting a user search operation, and the index management unit updates the index information when the information in the central server is updated, wherein, for the intermediate server, reference information including the field of information that the intermediate server specializes in and identification of the intermediate server is registered in the central server, the central server identifying, upon receipt of new information, the intermediate server associated with a field of the received new information, the central server sending update information to the identified intermediate server to notify the intermediate server of the receipt of the new information, and the index management unit contained in each of the intermediate server updating the index information according to the update information sent from the central server.