How can the world wide web be applied in an intranet and extranet?

The "Word-wide-web" by definition is world wide. An "intranet" by definition is not world wide and closed off from the world. As the two are diametrically opposed you can not apply the world-wide-web in an intranet. However the standards and tools used to deliver the world-wide-web can be used in an intranet.