Final answer:
An extranet is a private network that uses Internet technologies to interconnect different organizations, allowing secure information sharing and collaboration. It evolved from earlier networks like ARPANET, designed for government and academic communication, and has become crucial to global commerce and communication.
Step-by-step explanation:
An extranet is a private network that employs Internet technologies to connect more than one organization. This type of network facilitates communication, collaboration, and the sharing of information across different organizations. This technology stems from the same roots as the Internet; where the latter is accessible to the general public, an extranet remains restricted to specific, interconnected entities.
The concept of computer networks emerged as early as the 1960s with the development of ARPANET, aimed at facilitating official communication within government and academic circles. Over time, computer networks evolved, becoming vital to various sectors including government, institutions, and corporations, as predicted by JCR Licklider's "Intergalactic Computer Network". These networks extend beyond individual countries, building economic and political connections that transcend nation-state boundaries.
By the 1980s, these networks saw standardization in communication protocols, leading to the modern Internet we know today, and subsequently, the World Wide Web. As the virtual world becomes increasingly significant to the global economy, networks like extranets have gained prominence, allowing businesses and organizations to share information and resources securely among one another, just as the SABRE system did for airline reservations.