Patent Publication Number: US-2005138027-A1

Title: Filtering server, filtering system, and filtering method

Description:
CROSS REFERENCE TO RELATED APPLICATIONS  
      The disclosure of Japanese Patent Application No. JP2003-419873, filed Dec. 17, 2003, entitled “Filtering System”. The contents of that application are incorporated herein by reference in their entirety.  
     BACKGROUND OF THE INVENTION  
      1. Field of the Invention  
      The present invention relates to a filtering server, a filtering system, and a filtering method which filter information to be delivered to a user.  
      2. Description of the Related Art  
      In the specification of Japanese Patent Laid-open Publication No. 2003-30527, a technique that provides appropriate information to a user through a communication network is disclosed.  
      In the technique disclosed in the specification Japanese Patent Laid-open Publication No. 2003-30527, a user (demander) inputs a bar code attached to a commercial product or a service to make it possible to obtain information related to the commercial product or the service. In this case, information which can be obtained is information associated with the bar code.  
      On the other hand, some search site actually managed has an insertion system which inserts an advertisement linked to a keyword.  
      In the advertisement insertion system, an object to be retrieved is a Web page on the internet. An information provider who intends to place an advertisement on a page serving as a retrieval result enters the search site as a sponsor.  
      When a user who operates a Web browser inputs a keyword, location data (URL) of a Web page which is matched with the keyword and a part of the content of the Web page are displayed as a list.  
      When the keyword is matched with sponsor information, it is clearly specified that the information is sponsor information, and the information is displayed on the screen of the Web browser as a part of a retrieval result. The sponsor information includes a sponsor name, a URL, or an outline of a Web page designated by the URL.  
      The search site obtains a charge from the sponsor company as a price for displaying the sponsor information on a browser screen together with a retrieval result.  
     SUMMARY OF THE INVENTION  
      In the advertisement insertion system disclosed above, each time a keyword is matched with sponsor information, the sponsor information must be repetitively displayed on a browser screen. In addition, when the same uninteresting sponsor information is displayed on the screen again and again, the sponsor information is disliked by a user. In addition, consequently, the user rarely read the sponsor information to deteriorate the advertising effectiveness.  
      On the other hand, in the technique described in the specification of Japanese Patent Laid-open Publication No. 2003-30527, a user changes demander desired information or a demander notification condition in advance to make it possible to change available information. However, the demander desired information or the demander notification condition is changed to increase an operation load on a user. As a result, the usability is deteriorated.  
      In order to solve the above problem, according to an aspect of the present invention, there is provided a filtering server which filters specific information desired by an information provider to be recognized by a user depending on a desire of the user and which transmits specific information which is not excluded by the filtering to the user, including: a keyword acquiring section for acquiring a keyword input by the user; a specific information accumulating section for accumulating a plurality of pieces of specific information; a specific information retrieving section for retrieving specific information desired to be browsed by the user from the specific information accumulating section on the basis of the keyword acquired by the keyword acquiring section; a specific information presentation recording section for storing the specific information retrieved by the specific information retrieving section and a recording information of the specific information; a specific information presentation control section for extracting at least one piece of specific information from the pieces of specific information stored in the specific information presentation recording section depending on the recording information of the specific information presentation recording section; and a specific information presentation section for presenting the specific information extracted by the specific information presentation control section to the user.  
      The recording information may be presentation status information representing a status in which the specific information has been presented to the user until now, and the specific information presentation control section can extract only specific information which has not been presented to the user until now.  
      The recording information may be content updating information representing whether the specific information is updated after the specific information is previously presented to the user and whether the specific information has been presented to the user until now, and the specific information presentation control section can extract only the updated specific information and specific information which has not being presented to the user until now.  
      The filtering server may be further comprising a setting screen presentation section for collecting specific information desired by a user through a setting Web page, a difference acquiring section for acquiring a Web page at regular or irregular intervals on the basis of an input content collected by the setting screen presentation section, and extracting a difference between the Web page and a previously acquired Web page; and an updating information presentation section for presenting the difference extracted by the difference extracting section to the user.  
      In order to solve the above problem, according to another aspect of the present invention, there is provided a filtering system which includes a communication terminal used by a user and also includes a filtering server which is connected to the communication terminal through a communication network and which filters specific information desired by an information provider to be recognized by the user depending on a desire of the user and which transmits specific information which is not excluded by the filtering to the user, wherein the communication terminal includes: an input section for inputting a keyword; and an output section for outputting a result obtained by the filtering, and the filtering server includes: a keyword acquiring section for acquiring a keyword input by the user via the communication terminal; a specific information accumulating section for accumulating a plurality of pieces of specific information; a specific information retrieving section for retrieving specific information desired to be browsed by the user from the specific information accumulating section on the basis of the keyword acquired by the keyword acquiring section; a specific information presentation recording section for storing the specific information retrieved by the specific information retrieving section and a recording information of the specific information; a specific information presentation control section for extracting at least one piece of specific information from the pieces of specific information stored in the specific information presentation recording section depending on the recording information of the specific information presentation recording section; and a specific information presentation section for presenting the specific information extracted by the specific information presentation control section to the output section.  
      In order to solve the above problem, according to still another aspect of the present invention, there is provided a filtering method which filters specific information desired by an information provider to be recognized by a user depending on a desire of the user and which transmits specific information which is not excluded by the filtering to the user, including: the keyword acquiring step of acquiring a keyword input by the user; the specific information retrieving step of retrieving specific information desired to be browsed by the user on the basis of the keyword acquired by the keyword acquiring step; the specific information presentation recording step of storing the specific information retrieved in the specific information retrieving step and a recording information of the specific information; a specific information presentation control step for extracting at least one piece of specific information from the specific information retrieved in the specific information retrieving step depending on the recording information of the specific information retrieved in the specific information retrieving step; and the specific information presentation step of presenting the specific information extracted in the specific information presentation control step to the user.  
      According to the present invention, a filtering system having high usability and high flexibility can be provided without excessively loading on a user. Furthermore, when specific information includes, e.g., an advertisement, advertising effectiveness can be improved. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       FIG. 1  is a schematic diagram showing the entire configuration of a filtering system.  
       FIG. 2  is a schematic diagram showing the configuration of a filtering server according to a first embodiment.  
       FIG. 3  is a schematic diagram showing a configuration of a user attribute information accumulating section.  
       FIG. 4  is a table showing data with which user attribute information and keywords are associated in advance.  
       FIG. 5  is a table showing a list of specific information accumulated in a specific information accumulating section.  
       FIG. 6  is a table showing a list of specific information with which keywords are associated.  
       FIG. 7  is a diagram showing presentation state information stored in a specific information presentation recording section.  
       FIG. 8  is a schematic diagram showing a configuration of a Web page returned as a response.  
       FIG. 9  is a schematic diagram showing the configuration of a filtering server according to a second embodiment.  
       FIG. 10  is a diagram showing content updating information stored in a specific information presentation recording section.  
       FIG. 11  is a diagram showing data stored in the specific information presentation recording section.  
       FIG. 12  is a schematic diagram showing the configuration of a filtering server according to a third embodiment.  
       FIG. 13  is a schematic diagram showing a configuration of a setting screen.  
       FIG. 14  is a schematic diagram showing an example of accumulated contents of a difference acquiring section.  
       FIG. 15  is a schematic diagram showing a configuration of a Web page returned as a response. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS  
      Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. In this specification and the drawings, the same reference numerals denote components substantially having the same functions, respectively, and overlapping descriptions will not be repeated here.  
      Filtering systems according to the embodiments will be described below such that the filtering systems are applied to a communication system connected through a communication network.  
     First Embodiment: Filtering System  
       FIG. 1  is a schematic diagram showing the entire configuration of a filtering system  10  according to the embodiment.  
      In  FIG. 1 , the filtering system  10  includes a network  11 , a filtering server  12 , a content server  13 , and a communication terminal  14 .  
      The network  11  is a communication network such as a LAN (local area network) or the internet. In the embodiment, the network  11  is the internet.  
      The filtering server  12  and the content server  13  are Web servers, respectively. The content server  13  is a usual Web server managed by a sponsor serving as the information provider (in this case, called an EP 1 ). The filtering server  12  is a component corresponding to the search site, and is a Web server serving as a characteristic feature of the embodiment. It is assumed that the filtering server  12  is managed by a carrier FP 1 .  
      The communication terminal  14  is a communication terminal on which a Web browser BR 1  serving as a client function for the Web server is mounted, and is operated by a user U 1 . The communication terminal may be, e.g., a personal computer.  
       FIG. 2  is a schematic diagram showing the configuration of the filtering server  12  serving as a Web server.  
      In  FIG. 2 , the filtering server  12  includes a user attribute information accumulating section  101 , a keyword acquiring section  102 , a specific information accumulating section  103 , a specific information retrieving section  104 , a specific information presentation control section  105 , a specific information presentation section  106 , and a specific information presentation recording section  107 .  
      The user attribute information accumulating section  101  stores attribute information of a user (for example, U 1 ). The attribute information includes at least information which can uniquely specify a user in the filtering server  12 . The information which can uniquely specify the user is, e.g., a user ID allocated to each user in the filtering server  12 . The attribute information may also include sex, age, occupation, habitation area, mail address, and the like acquired from the user. In this case, the data accumulated in the user attribute information accumulating section  101  is as shown in  FIG. 3 . In  FIG. 3 , the user ID, the mail address, the sex, the age, the occupation, and the habitation area are associated with each other.  
      The keyword acquiring section  102  acquires a keyword input by the user U 1  and associates the keyword with the user U 1 . An input screen is transmitted from the filtering server  12  to the communication terminal  14  as a Web page on which a keyword can be input. The user U 1  inputs a keyword through the input screen.  
      The keyword acquiring section  102  may acquire a keyword depending on the user U 1  with reference to data with which user attribute information and a keyword are associated.  FIG. 4  is an example of a table showing these data. As the user attribute information, the user ID is used.  
      The specific information accumulating section  103  accumulates specific information to be presented by an information provider (e.g., EP 1 ) to a user. The specific information includes the name of an information provider presented to the user, the URL of a Web page provided by the information provider, the outline of the Web page, and the like. In this manner, the specific information include various pieces of information corresponding to the sponsor information.  FIG. 5  is a table showing a list of specific information accumulated in the specific information accumulating section  103 . In this case, the name of an information provider, a URL, and an outline of a Web page are cited as examples. The specific information accumulating section  103  accumulates the contents of the Web pages themselves as needed.  
      The specific information accumulating section  103  may extract keywords included in pieces of specific information in advance and accumulates the keywords with association with the pieces of specific information.  FIG. 6  is a table showing a list of the pieces of specific information with which the keywords are associated. In this case, the name of an information provider, a URL, and an outline of a Web page serving as the pieces of specific information are associated with keywords. With the configuration, specific information can be easily retrieved by a keyword input by the user.  
      The specific information retrieving section  104  retrieves specific information on the basis of a keyword acquired by the keyword acquiring section  102 . An object to be retrieved is basically a Web page corresponding to a URL or an outline of the Web page in the specific information accumulated in the specific information accumulating section  103 . As needed, a retrieval range is limited to the outline of the Web page to reduce a processing load on the filtering server  12  and improve response capability.  
      When the number of users who use the filtering server  12  increases, the information provider can more effectively notify the users of the specific information. Therefore, the accumulated contents of the specific information accumulating section  103  becomes abundant, and the specific information matched with the keyword input by the user is not easily absent in the specific information accumulating section  103 .  
      The specific information presentation recording section  107  records a recording information. In the embodiment, the recording information is presentation status information representing a status in which specific information has been presented to a user until now. As the recording information (presentation status information) of the embodiment, information representing whether the specific information is presented or unpresented to the user is recorded. Data stored in the specific information presentation recording section  107  is as shown in  FIG. 7 . As shown in  FIG. 7 , a presented record is left because the specific information as the presented specific information is prevented from being repetitively presented to the user U 1 . In addition, as in L 2  and L 3  of the presentation status information, values are extemporaneously unpresented with passing time. Normally, only presented values are displayed.  
      The specific information presentation control section  105  controls whether the specific information is presented on the basis of the presentation status information recorded on the specific information presentation recording section  107 . Basically, on the basis of the record representing whether the specific information is presented, the specific information which has been presented is not presented. However, when the user U 1  operates a hyperlink (URL) in a Web page corresponding to the specific information to access a new Web page to another link (URL destination) in past presentation, the specific information can be presented again even though the specific information has been presented. In this case, the access to the new Web page must be recorded in the specific information presentation recording section  107  as a part of the presentation status information.  
      The specific information presentation section  106  executes presentation of specific information under the control of the specific information presentation control section  105 . More specifically, under the control of the specific information presentation control section  105 , Web pages to be presented are generated to users (one of the users is the user U 1 ), respectively, and the Web pages are returned to the users as a part of an HTTP response message.  
     Operation of First Embodiment  
      An operation of the embodiment having the above configuration will be described below.  
      It is assumed that the user U 1  accesses the filtering server  12  through the Web browser BR 1  and that the user ID of the user U 1  corresponds to “0001” shown in  FIGS. 3, 4 , and  7 .  
      As is apparent from  FIG. 7 , the user ID is “0001” in three lines L 1  to L 3 . The specific information (also including a URL itself) designated by a URL (in this case, http://www.mm-sports.aaa) corresponding to the uppermost line (i.e., the line L 1 ) in  FIG. 7  has been presented. The specific information corresponding to the URL of the line L 2  serving as the second upper line is not presented. The specific information corresponding to the URL of the line L 3  serving as the third upper line is not presented. However, when an HTTP request message from the user U 1  is received, it is assumed that the lines L 2  and L 3  in  FIG. 7  are not present and that the presentation status information is constituted by only a presented line in  FIG. 7 .  
      In this state, it is assumed that the user U 1  accesses the filtering server  12  through the Web browser BR 1  of the communication terminal  14  and transmits a keyword through the input screen. The keyword is delivered from the Web browser BR 1  (communication terminal  14 ) to the filtering server  12  as a part of an HTTP request message RQ 1 . The keyword included in the HTTP request message RQ 1  is acquired by the keyword acquiring section  102 .  
      At this time, the filtering server  12  must specify a user who accesses to the filtering server  12  by some method as the user U 1 . The user can be specified by various methods. For example, when the filtering server  12  provides a members-only service, the filtering server  12  can specify a user by causing the user to declare a member ID. Furthermore, a user can also be specified by using cookies or the like. When a user can specified as the user U 1 , it can be understood that the user ID of the user is the “0001”.  
      The specific information retrieving section  104  retrieves specific information, e.g., an outline of a Web page or the Web page itself, serving as an accumulated content of the specific information accumulating section  103  on the basis of the keyword input by the user. The specific information retrieving section  104  collects the outline of the Web page matched with the keyword and the URL of the Web page by, e.g., a method shown in  FIG. 5 . At this time, for example, as shown in  FIG. 6 , a keyword extracted from the outline of the Web page is extracted in advance and registered in the specific information accumulating section  103  in association with each URL to make it easy to retrieve the outline of the Web page.  
      The accumulated contents of the specific information accumulating section  103  are abundant, the number of outlines of Web pages including a character string matched with the keyword or the number of Web pages increases, and the number of collected URLs also increases. Therefore, a set of URLs (URL set) including a large number of URLs as elements is formed. In this case, a URL set S 1  including n URLs (URL 1 , URL 2 , . . . , URLn) as elements is formed. The specific information presentation control section  105  acquires the URL set S 1  and “0001” serving as the user ID.  
      The specific information presentation control section  105  specifies a line corresponding to the user ID in lines L 1 , L 4 , and L 5  in the specific information presentation recording section  107  (there are no lines L 2  and L 3  at this time). When the data stored in the specific information presentation recording section  107  is obtained by removing the lines L 2  and L 3  from the lines in  FIG. 7 , only the line L 1  in  FIG. 7  corresponds to the user ID “0001” (i.e., the user U 1 ).  
      The specific information presentation control section  105  compares the URLs serving as the elements of the URL set S 1  with the URL of the line L 1 , and adds at least one line corresponding to at least one element which is not matched with the URL of the line L 1  to the specific information presentation recording section  107 . In this case, the user ID of the line to be added is “0001”, the value of the URL is the URL itself, and the value of the presentation status information is “unpresented”.  
      In the embodiment, the URLs corresponding to the two lines L 2  and L 3  are added, and the data stored in the specific information presentation recording section  107  has a state shown in  FIG. 7 .  
      When a plurality of keywords transmitted through the HTTP request message RQ 1 , the same process is repeatedly executed. Each the process is executed, a new line can be added as described above. In the embodiment, for descriptive convenience, only one keyword is included in the HTTP request message RQ 1 , and only the lines L 2  and L 3  are added.  
      Upon completion of the addition of the lines to the HTTP request message RQ 1 , the specific information presentation control section  105  gives a control right to the specific information presentation section  106 . The specific information presentation section  106  extracts the URLs corresponding to the two lines L 2  and L 3  in which the values of presentation state information are unpresented in the data (in  FIG. 7 ) in the specific information presentation recording section  107  and acquires the name and/or URL of an information provider designated by the URL and/or the outline of a Web page from the specific information accumulating section  103 . However, in this case, only the name and URL of the information provider are acquired.  
      As is apparent of comparison between the URLs included in  FIGS. 5 and 7 , the line corresponding to the URL of the line L 2  in  FIG. 7  is a line LN 2  in  FIG. 5 , and the line corresponding to the URL of the line L 3  in  FIG. 7  is a line LN 3  in  FIG. 5 . Therefore, “xx company” and “□□ industry” are acquired as the names of information providers, and “http://www.xx-comp.bbb” and “http://www.yy-comp.ccc” are acquired as URLs.  
      The specific information presentation section  106  generates a Web page as shown in, e.g.,  FIG. 8  on the basis of the acquired pieces of information and returns the Web page to the Web browser BR 1  as a part of an HTTP response message RS 1 . The HTTP response message RS 1  is a response to the HTTP request message RQ 1  described above.  
      The Web browser BR 1  of the communication terminal  14  which receives the HTTP response message RS 1  displays a Web page shown in  FIG. 8  on a screen. Therefore, the user U 1  can visually check the screen. Since displays LK 1  and LK 2  of the URLs displayed in  FIG. 8  are hyperlinks, the user U 1  who operates the communication terminal  14  clicks the hyperlink to acquire a linked Web page, and can browse the Web page.  
     Effect of First Embodiment  
      According to the embodiment, since a Web page in which a browsing history of each of users (one of the users is the user U 1 ) can be returned to the user, even though time the user inputs the same keyword, specific information (e.g., the name of an information provider, a URL, the outline of a Web page, and the like) to be browsed on Web pages changes each time, and a trouble of viewing the same specific information a number of times can be eliminated. Therefore, the filtering server of the embodiment has the usability and the flexibility.  
      With the configuration, the user can always view new specific information, and can easily find specific information related to information in which the user is interested. Therefore, the user can easily reach desired information.  
      This also contributes to improvement in advertising effect when specific information is an advertisement or the like.  
     Second Embodiment: Filtering System  
      Only points of difference between the second embodiment and the first embodiment will be described below.  
      The embodiment is different from the first embodiment in that the recording information of the specific information presentation recording section  107  is content updating information but presentation state information.  
      For example, the content updating information is recording information representing whether the content of the Web page corresponding to the specific information is updated from time when the specific information is presented to the previous user (e.g., u 1 ), i.e., information representing whether the content is a new content for the user.  
      Functions other than the function related to the content updating information of the embodiment are the same as those in the first embodiment.  
     Configuration and Operation of Second Embodiment  
       FIG. 9  is a schematic diagram showing the configuration of a filtering server  20  according to the embodiment.  
      In  FIG. 9 , since the functions of components  201  to  207  to which the same names as those in  FIG. 1  are given the same as those in the first embodiment, and a description thereof will not be repeated here.  
      Data stored in a specific information presentation recording section  207  is as shown in, e.g.,  FIG. 10 . The specific information presentation recording section  207  is different from the specific information presentation recording section  107  according to the first embodiment in that the specific information presentation recording section  207  records, as recording information, the content updating information, i.e., “unupdated”, “updated”, and “new”.  
      In this case, “unupdated” means that the content of a Web page is not updated from time when the content is previously presented to the user (e.g., a user U 1 ). “Updated” means that the content of a Web page is updated from time when the content is previously presented to the user (e.g., the user U 1 ). “New” means that a Web page is a new Web page which never be presented to the user (e.g., the user U 1 ).  
      A specific information updating detecting section  208  serving as a component of the filtering server  20  according to the embodiment acquires these pieces of content updating information related to the Web page corresponding to specific information. The content updating information may be acquired from HTTP control information by using a HEAD method or the like. However, in this case, the content (body of the content) of the Web page is acquired and compared with the content of the Web page which is previously acquired to check whether the contents are different from each other, thereby acquiring the contents updating information. A method of checking whether the body of the content is different from that of the content of the previously acquired Web page heavily loads the processing ability of the filtering server  20  in comparison with a method using HTTP control information. However, although the detail of the body of a content is not updated, the specific information updating detecting section  208  can prevent from erroneously determine that the detail is updated when only the time stamp of the content is updated. Therefore, more accurate and exact information can be advantageously obtained.  
      When the user U 1  uses the filtering server  20 , data which has been stored in the specific information presentation recording section  207  includes a line corresponding to the user U 1 .  FIG. 10  is a diagram showing content updating information stored in the specific information presentation recording section  207 . In this case, user ID “0001” correspond to three lines LM 1  to LM 3 .  
      The specific information updating detecting section  208  updates a recorded content in the specific information presentation recording section  207  into a new content by automatic processes even though any request is not received from the user U 1 . The processes may be executed at regular or irregular intervals.  
      For example, in the line LM 1 , the filtering server  20  transmits an HTTP request message to “http://www.mm-sports.aaa” to make it possible to acquire a content body. However, the filtering server  20  itself has a function of content server (i.e., a function of a Web server of some content provider), the filtering server  20  accesses a file managed by the filtering server  20  itself to acquire the content body.  
      The filtering server  20  transmits an HTTP request message to the “http://www.mm-sports.aaa” and receives an HTTP response message serving as a response of the HTTP request message from the content server  13 . Thereafter, the specific information updating detecting section  208  compares the body of the latest content included in the HTTP response message with a content body previously acquired and accumulated in a specific information accumulating section  203  or the like to check whether the previously acquired content is replaced with the latest content.  
      When it is determined in the check that the content is not updated, with respect to a corresponding line (in this case, the line LM 1 ) of the data stored in the specific information presentation recording section  207 , the value of the content updating information is kept at the previous value, e.g., “unupdated”. When it is determined that the content is updated, the value of the content updating information is changed into “updated”. For example,  FIG. 11  shows data stored in the specific information presentation recording section  207  and obtained a period of time after the time set in  FIG. 10 . As is apparent from comparison between  FIG. 11  and  FIG. 10 , the value of the content updating information of the line LM 1  is changed from “unupdated” to “updated”. This change reflects that a character string “New product AAA was announced.” in the content body is changed into a character string “New product xxx was announced.”.  
      When it is determined that the content is not updated, the value of the content updating information of the corresponding row (in this case, the line LM 1 ) is kept at the previous value. This is because “updated” obtained as a result of the previous check since the check is repeated at regular or irregular intervals. Therefore, with respect to a line in which “updated” is recorded in the content updating information as the result of the previous check, the record “updated” is kept after the latest check until the content of the Web page is presented to the user.  
      Of the values of the content updating information, an order of processes in which “new” is recorded will be described below. A keyword acquiring section  202  corresponding to the keyword acquiring section  102  in the first embodiment acquires a keyword delivered by an HTTP request message RQ 1 . A specific information retrieving section  204  corresponding to the specific information retrieving section  104  according to the first embodiment retrieves an accumulated content of a specific information accumulating section  203  corresponding to the specific information accumulating section  103  in the first embodiment on the basis of the keyword to obtain a URL set S 1 . The processes performed until now are the same as those in the first embodiment.  
      When data stored in the specific information presentation recording section  207  when the HTTP request message RQ 1  is delivered from the user U 1  does not include a line LM 3  in  FIG. 10 , and when the elements of the URL set S 1  include the URL of the line LM 3 , the line LM 3  in which the value of the content updating information in the data of the specific information presentation recording section  207  is “new” is added.  
      Therefore, the meaning of “new” in the embodiment is equal to “unpresented” in the first embodiment, and is handled like “unpresented” in the first embodiment.  
      More specifically, specific information in which the content updating information is “new” is presented to the user U 1 . In the embodiment, specific information in which the content updating information is “updated” is also presented to the user U 1 .  
      More specifically, the specific information presentation section  206  generate the Web page of similar  FIG. 8  including specific information in which the content updating information corresponds to “new” or “updated”. The Web page is returned to the user U 1  as a part of the HTTP response message RS 1  serving as a response of the HTTP request message RQ 1 .  
      Together with the display LK 1  or LK 2  shown in  FIG. 8 , information representing the content updating information of the specific information denoted by the display is “new” or “updated” may be shown to the user U 1 .  
      In the specific information updating detecting section  208 , content bodies are compared with each other to make it possible to specify an exact updated content. For this reason, the updated content can also be added to the Web page.  
      For example, the number of characters in which the old and new content bodies are different from each other, a new word with which a specific word (complex word, sentence, or the like) in the old content is replaced, or the like may be simply displayed on the Web page. As the outline of the Web page, a part the content of which is changed by the updating may be displayed.  
      Even though the content body is updated, when the detail of the content body is not substantially changed, e.g., when wrong letters or missing characters are corrected, the updating is understood as not so much significant updating for a normal user. For this reason, the significance of updating is decided, and the updating is processed as “updated” only when it is understood that the updating is significant.  
      The decision of the significant of updating may also use natural language processing. For example, it can be decided whether updating is significant or not by checking whether a content to be updated include a specific character string.  
      For this reason, for example, a rule for deciding a quantity or content of a change such as a change of only date information or a change of characters the number of which is equal or smaller than a predetermined number is set. When a condition is matched with the rule, processing which does not decide the change as updating can also be performed.  
     Effect of Second Embodiment  
      According to the embodiment, an effect which is approximately equivalent to the effect of the first embodiment can be obtained.  
      In addition, in the embodiment, when specific information corresponding to an unupdated content is not presented to a user, and when the detail of a content body is changed by updating, specific information corresponding to the content is presented to the user. Therefore, when the user inputs only the same keyword, the user can know fresh specific information related to the keyword.  
      A user need not browse Unchanged specific information. This regard considerably contributes to a reduction in load on the user.  
     Third Embodiment: Filtering System  
      A difference between this embodiment and the first and second embodiments will be described below.  
      A characteristic feature of the embodiment, the presence of updating is checked with respect to at least one Web page designated by a URL input by a user (U 1 ) himself such that the user (U 1 ) uses a predetermined setting screen, thereby notifying the user of the presence of updating.  
      Functions other than the function related to the setting screen in the embodiment are the same as those in the second embodiment.  
      Since the embodiment includes a specific information updating detecting section  308  (refer to  FIG. 12 ), it is understood that the embodiment is closer to the second embodiment than the first embodiment.  
     Configuration and Operation of Third Embodiment)  
       FIG. 12  is a schematic diagram showing the configuration of a filtering server  30  according to the embodiment.  
      In  FIG. 2 , since the functions of components  302  to  305 ,  307 , and  308  to which the same names as those in  FIG. 9  are added are basically the same as the functions in the second embodiment, a description thereof will not be repeated here.  
      As other components, the filtering server  30  includes a setting screen presentation section  300 , an updated information presentation section  306 , and a difference acquiring section  309  shown in  FIG. 12 .  
      The setting screen presentation section  300  generates a setting screen (Web page for setting) WP 1  as shown in, e.g.,  FIG. 13  and provides the setting screen WP 1  to a Web browser BR 1  of the user U 1 . The user directly inputs a URL or the like in the setting Web page WP 1 . The setting screen presentation section  300  uses a device having the above form to collect input contents of the user U 1 .  
      In  FIG. 13 , the user U 1  operates the communication terminal  14  to make it possible to input fields FD 1 , FD 2 , and FD 5  and click boxes BX 1  and BX 2  on the Web browser BR 1 .  
      The fields FD 1  and FD 2  of these fields are URL input fields for dynamically describing the URLs of Web sites in which the user U 1  is interested when the user U 1  inputs the fields.  
      The URLs of fields FD 3  and FD 4  are URLs of specific information accumulated in the filtering server  30 .  
      The click boxes BX 1  and BX 2  are boxes which are clicked by the user U 1  on the communication terminal  14  to select desired specific information. In this case, a plurality of pieces of specific information can be simultaneously selected, or only one piece of specific information can be selected. It is naturally possible that any specific information is not selected.  
      The field FD 5  is a field in which an address to which the filtering server  30  notices a result obtained by checking the presence of updating related to a Web page designated by the user U 1  through selection of the fields FD 1  and FD 2  or the click boxes BX 1  and BX 2 . In an example in  FIG. 13 , an electronic mail address of the user U 1  is described. A check result can be returned as an HTTP response message. This check may requires an access to another Web server (for example, the content server  13  in  FIG. 1 ). An electronic mail is used in the example in  FIG. 13  to prevent response time from being excessively long. This electronic mail may be a so-called mail magazine obtained by collecting, e.g., the contents of an updated Web page.  
      The user U 1  operates a “transmission” button BT 1  upon completion of inputting to the respective sections of the setting Web page WP 1 . In this manner, the input content is transmitted to the filtering server  30  as an HTTP request message.  
      An operation procedure in the embodiment performed on the assumption that the setting Web page WP 1  is acquired by the user U 1  is different from an operation procedure in the embodiment performed when subsequent processes are performed without passing through the setting Web page WP 1 . Therefore, the configurations of Web pages (also including a Web page (not shown)) presented by the filtering server  30  to the user U 1  are different from each other. A case in which the subsequent processes are started through the setting Web page WP 1  is described here.  
      It is assumed that the subsequent processes are executed through only the setting Web page WP 1 . In this case, when the user U 1  views the setting Web page WP 1  for the first time, as a matter of course, the user U 1  also uses the filtering server  30  for the first time, and any information related to the user U 1  is not accumulated in the specific information presentation recording section  307  and the specific information accumulating section  303 .  
      In this case, on an initialized setting Web page WP 1  transmitted from the filtering server  30  and displayed on the browser screen of the communication terminal  14 , all the fields FD 1  to FD 5  and the click boxes BX 1  and BX 2  are blank.  
      On the setting Web page WP 1  in this state, the user U 1  can input only the fields FD 1 , FD 2 , and FD 5 .  
      The number of input fields of the setting Web page WP 1  is not limited to the number of items shown in  FIG. 13 . In addition, fields for inputting keywords can also be arranged for designation information and specific information.  
      When the user U 1  browses the setting Web page WP 1  again, the specific information accumulating section  303  and the specific information presentation recording section  307  have included lines corresponding to the user U 1 . For this reason, even on the setting Web page WP 1  which has been provided just now, URLs have been input in the fields FD 1  to FD 4 , respectively. The setting screen presentation section  300  directly performs this input process. The accumulated content of the specific information accumulating section  303  is reflected in the input content.  
      For example, when the setting screen presentation section  300  generates the second setting Web page WP 1  for the user U 1 , the URL input by the user U 1  in the first presentation may be described in the fields FD 1  and FD 2  on the setting Web page WP 1  each, and the URL of specific information matched with a keyword included in the Web page designated by the URL input by the user U 1  may be described in the fields FD 3  and FD 4  each.  
      Even in the second and subsequent browsing operations, all the fields FD 1  to FD 5  may not be filled.  
      The difference acquiring section  309  acquires a Web page at regular or irregular intervals on the basis of the input content (for example, URL) collected by the setting screen presentation section  300 , extracts a difference between the previously acquired Web page and the Web page acquired at the present, and accumulates the difference. This difference may be accumulated in association with at least a user ID and a URL, and may also be accumulated in association with the content of the acquired Web page as needed. When the entire content of the Web page is also accumulated in association with the difference, the configuration of the data accumulated in the difference acquiring section  309  is shown in  FIG. 14 .  
      A keyword acquiring section  302  extracts a character string corresponding to a keyword from the difference acquired in the difference acquiring section  309 . The method of extracting a keyword is not specifically determined. A conventional technique is applied as the method. The keyword acquiring section  302  is desirably interlocked with the difference acquiring section  309 . This is because, when the difference acquiring section  309  completely records a series of pieces of information, the keyword acquiring section  302  can effectively start acquisition of a keyword.  
      When not only the difference acquired by the difference acquiring section  309  but also the entire content of the Web page as shown in  FIG. 14  are accumulated, the keyword acquiring section  302  may extract a character string corresponding to a keyword from the entire content of the Web page. In any case, the method of extracting a keyword from the acquired information or the difference is not specified. However, a technique which handles a title portion as a keyword, a technique which handles, as a keyword, a character string frequently appearing in specific character strings included in a document to be acquired, or a technique which handles, as a keyword, a word determined as a noun after syntactic analysis, or the like is applied to make it possible to acquire a keyword.  
      The updated information presentation section  306  specifies a line (for example, a line LP 1  in  FIG. 14 ) corresponding to a URL indicated by information (input contents in the fields FD 1  to FD 4  and the click boxes BX 1  and BX 2 ) collected from the setting screen presentation section  300  and presents the difference and the URL included in the line to the user U 1 .  
      When the electronic mail is used in this presentation, the filtering server  30  transmits an electronic mail having a text portion shown in, e.g.,  FIG. 15  to an electronic mail address designated by the user U 1  in the field FD 5 .  
     Effect of Third Embodiment  
      According to the embodiment, an effect which is approximately equivalent to the effect of the second embodiment can be obtained.  
      In addition, in the embodiment, only when the content of the Web page designated by the user (U 1 ), the filtering server  30  notifies the user of the content of the updating. For this reason, the user can efficiently know updating of a Web page in which the user is interested.  
      When an information provider (for example, EP 1 ) merely updates the content of a Web page, the information provider can advantageously notify a user (for example, U 1 ) who is interested in the content of the Web page of the updated content.  
      A carrier FP 1  who manages the filtering server  30  can charge an information provider on the basis of an index depending on the number of users who receive an updated content. For this reason, the carrier FP 1  can provide a service to a user (for example, U 1 ) at low charge or for nothing.  
     Another Embodiment  
      In the first to third embodiments, specific information may be an advertisement of a sponsor.  
      The name of specific information may not be recorded in a filtering server (in this case, the name is not presented to a user as a matter of course).  
      When a URL is presented such that not only the URL but also information such as an outline of a Web page are associated with specific information, these pieces of information may be simultaneously presented as described above.  
      In the specific information accumulating section (for example,  103 ), a keyword may not be registered simultaneously with the URL of specific information. In this case, a keyword extracted by the specific information accumulating section may be recorded by a method in which a system looks ahead to the information of a Web page indicated by a URL (more specifically, the Web page indicated by the URL is acquired) and handles a title portion in the obtained information as a keyword, a method in which the system handles, as a keyword, a character string frequently appearing in specific character strings included in a document to be acquired, or a method in which the system handles, as a keyword, a word determined as a noun after syntactic analysis.  
      The accumulated contents (for example, the configurations shown in  FIGS. 3, 4 ,  5 ,  6 ,  7 ,  10 ,  11 , and  14 ) in the components according to the first to third embodiments are not limited to the contents described above, as a matter of course.  
      In addition, in the third embodiment, the following process may be additionally performed. That is, in  FIG. 13 , inputting of a character string is accepted in conjunction with a URL set by a user, and the character string is accumulated in the difference acquiring section  309 . When updating information is presented by the updated information presentation section  306 , it is decided whether a difference includes a previously set character string. When the difference includes the character string, the updating information is presented to the user.  
      Regardless of the first and second embodiments, presentation of specific information to a user may be achieved by transmission of an electronic mail. More specifically, an electronic mail having the same content as that in  FIG. 8  in the text portion may be transmitted to achieve presentation.  
      Even though the content of the URL of the specific information has been presented, when a predetermined period of time has elapsed, the value of recording information in the specific information recording section (for example,  107 ) may be changed into “unpresented” or “new”. It can be considered that the content is preferably presented again after a sufficient period of time has elapsed because the user probably forgets the content.  
      The electronic mail in the above description can also be replaced with another communication means.  
      In the first to third embodiments, although the present invention is applied to the Web, the present invention is not always applied to the Web.  
      In the present invention, communication through a network is not always necessary.  
      Therefore, the HTTP protocol can be replaced with another communication protocol, or a configuration which does not use the HTTP protocol can be employed.  
      For example, a configuration in which the function of the Web browser BR 1  and the function of the filtering server (for example, 12) are mounted in one information processing apparatus can also be used.  
      Although the present invention is mainly realized as hardware in the above description, the present invention can also be realized as software.  
      The preferred embodiments of the present invention have been described above with reference to the accompanying drawings. However, the present invention is not limited to the related examples, as a matter of course. It is apparent to a person skilled in the art that various changes and modifications of the invention can be effected in the spirit and scope of the invention. It is naturally understood that the changes and modifications belong to the scope of the invention.