Broadband Telecommunications Handbook, Second Edition

We begin with an attempt at a definition. Most of the buzzwords around the Internet are easy to define until we get to made-up words like intranet and extranet. These words were invented by journalists to describe Internet technology employed within an organization rather than outside the organization.
Intranet is essentially an Internet with a small i. In particular, it implies the web implementation on our internal internet. Now, what do we do about telecommuters of all descriptions? An answer is to give our telecommuters access to our intranet via the Internet, again using web technology.
Extranets are simply our Intranet extended to permit access to our organization by our business partners. That is, a web or a net interface designed specifically to support our business partners and field offices. This also could be a Virtual Private Network (VPN) if that level of security were required. You will note here the mixing of field offices and customers. If we were consistent, the field offices would be covered under intranet, while customers were covered under extranet.
Here again, when journalists make up words without clearly defining them, you get this interesting blurring of definitions.
By our definition, if the external employee (telecommuter and so on) has access to our internal network applications, then we are providing an intranet. That is, access isn't limited to our external web site, but extends to our internal web site and perhaps to File Transfer Protocol (FTP), telnet, and other...