Internet?Intranet?extranet?means

[Waqas]

Internet=Between the country,between the people and so on(msn,accagloble)
interanet=within the organization (such as in air line accounting software)
extranet=Is an internet but it allows some authorized person to access it(such as online banking,Online trading in stock exchange)

[Prajna B]

Hi
Hope you all enjoyed Christmas.:)

An extranet can be understood as a private intranet mapped onto the Internet or some other transmission system not accessible to the general public, but is managed by more than one company's administrator(s). For example, military networks of different security levels may map onto a common military radio transmission system that never connects to the Internet. Any private network mapped onto a public one is a virtual private network (VPN).
Another very common use of the term "extranet" is to designate the "private part" of a website, where "registered users" can navigate, enabled by authentication mechanisms on a "login page".

In contrast, an Intranet is a VPN under the control of a single company's administrator(s). An intranet can be understood as "a private version of an Internet," or as a version of the Internet confined to an organization. The term first appeared in print on April 19, 1995, in Digital News & Review in an article authored by technical editor Stephen Lawton

The Internet is a worldwide, publicly accessible series of interconnected computer networks that transmit data by packet switching using the standard Internet Protocol (IP). It is a "network of networks" that consists of millions of smaller domestic, academic, business, and government networks, which together carry various information and services, such as electronic mail, online chat, file transfer, and the interlinked web pages and other resources [COLOR="Blue"]World Wide Web (WWW).