The Internet is a global system of interconnected computer
 
networks that use the standardized Internet Protocol Suite

 (TCP/IP). It is a network of networks that consists of millions

of private and public, academic, business, and government

networks of local to global scope that are linked by copper

wires, fiber-optic cables, wireless connections, and other

technologies. The Internet carries a vast array of information

 resources and services, most notably the inter-linked hypertext
 
documents of the World Wide Web (WWW) and the

infrastructure to support electronic mail, in addition to
 
popular services such as online chat, file transfer and file
 
sharing, online gaming, and Voice over Internet Protocol

(VoIP) person-to-person communication via voice and video.

The origins of the Internet reach back to the 1960s when the
 
United States funded research projects of its military agencies

to build robust, fault-tolerant and distributed computer
 
networks. This research and a period of civilian funding of a
 
new U.S. backbone by the National Science Foundation

spawned worldwide participation in the development of new

networking technologies and led to the commercialization of

an international network in the mid 1990s, and resulted in the
 
following popularization of countless applications in virtually
 
every aspect of modern human life. As of 2009, an estimated

quarter of Earth's population uses the services of the Internet.