Like a network, Intranets are created to disseminate information and allow resource and application sharing within an organization.
Examples are system-wide email, newsgroups, chat and so on.
Web pages are developed like, and look like those found on the Internet. In this sense, they are like networks. Like networks, they don't have to be connected to the Internet at all. In effect, an Intranet is a site using Internet technology, placed behind corporate, educational, or other walls, set up so that outsiders can't get into it. Since then, the growth of intranets in the business world has been explosive.