What is Internet ?

The Internet is an infrastructure, in the sense in which that term is used to refer to the electricity grid, water reticulation pipework, and the networks of track, macadam and re-fuelling facilities that support rail and road transport. Rather than energy, water, cargo or passengers, the payload carried by the information infrastructure is messages.

The term 'Internet' has come to be used in a variety of ways. Many authors are careless in their usage of the term, and considerable confusion can arise. Firstly, from the perspective of the people who use it, the Internet is a vague, mostly unseen, collection of resources that enable communications between one's own device and devices elsewhere. Exhibit 3.2 provides a graphical depiction of that interpretation of the term 'Internet'.
http://www.anu.edu.au/people/Roger.Clarke/II/OzI04.html