The present invention relates to an information distribution system in which information mutually related as hypertexts to each other is distributed via a network.
The present invention particularly relates to a method of and an apparatus for distributing information, a method of and an apparatus for receiving information, a system for distributing information, and a program product for conducting information distribution in which when first information in an information providing unit is quoted by a second information, transmission of the first information from the information providing unit can be automatically limited or controlled.
Recently, the World Wide Web (WWW) has been increasingly employed as a system to provide information via the Internet. In many cases, information used by the WWW is hypertext described in the hypertext markup language (HTML). It is possible in the HTML to describe quotation of and reference to information by a notation called uniform resource identifier (URI). The URI is described, for example, in “HTTP: Hypertext Transfer Protocol” Chapter 13, pages 161 to 176 of “TCP/IP Illustrated, Volume 3 written by W. Richard Stevens and published from Addison-Wesley Publishing Company. According to description of this literature, the URI is used to identify a particular resource available via the hypertext transfer protocol (HTTP). The HTTP is a representative protocol used in the WWW and its outline is described in the literature above. In short, this is a protocol to transmit information in which an information requesting unit sends a request to an information providing unit, and the providing unit sends in response to the request a response to the requesting unit.
The WWW provides information using an information providing unit connected to a network called Web server.
Software called Web browser is ordinarily used to request and to display information. The Web browser is software which requests information from the Web server to display the information. The Web browser can acquire, according to description of hypertext described in the HTML, information from a Web server connected to a network to display the information. In many cases, the Web browser can display multimedia information including images and sounds.
The Web browser has ability in many cases to attain program codes called Java applet via a network and to execute the Java applet. The Java applet is described, for example, in pages 9 to 13 of “Java in a Nutshell, Second Edition” written by David Flanagan and published from O'Reilly & Associates, Inc. in May 1997.
Information can be quoted and referred to by the HTML description without paying attention to which one of the servers provides the information. This consequently promotes development of relationships between information to be provided and effective uses of the information. On the other hand, there arise problems, for example, the information quoted is used apart from a purpose of a person who has originally provided the information and/or an operation to refer to the information is against interests of the person.