When a "Web" Site is developed for the benefit of your internal constituency and made available through your LAN, or local area network, it is called an intranet.
When a "Web" Site is developed for the private use of both internal and external parties and made available through the Internet or a VPN (virtual private network), it is called an extranet.
In both cases it is the enabling power of Web technology that makes them possible at reasonable cost.
Intranet and extranet sites serve a variety of useful purposes and can play a role in the efficiency and success of your organization. Your infolane representative can help you understand the benefits and costs of developing your site.