Internet
The Internet is the global system of interconnected computer networks that use the Internet protocol suite (TCP/IP) to link devices worldwide. It is a network of networks that consists of private, public, academic, business, and government networks of local to global scope, linked by a broad array of electronic, wireless, and optical networking technologies. The Internet carries a vast range of information resources and services, such as the inter-linked hypertext documents and applications of the World Wide Web (WWW), electronic mail, telephony, and file sharing.
Internet
The index of a search engine can be thought of as analogous to the stars in sky. What we see has never existed, as the light has traveled different distances to reach our eye. Similarly, Web pages referenced in an index were also explored at different dates and they may not exist any more.
Ricardo Baeza-Yates and Berthier Ribeiro-Neto, in Modern Information Retrieval (1999), Addison-Wesley/ACM Press, p. 382.
