On my to-do list ;)
An intranet is a restricted-access network that works like the Web, but isn't on it. Usually owned and managed by a company, an intranet enables a company to share its resources with its employees without confidential information being made available to everyone with Internet access.
Refers to an intranet that is partially accessible to authorized outsiders. Whereas an intranet resides behind a firewall and is accessible only to people who are members of the same company or organization, an extranet provides various levels of accessibility to outsiders. You can access an extranet only if you have a valid username and password, and your identity determines which parts of the extranet you can view
