HTML and CSS Reference
The Internet was developed in the 1960s by the Department of Defense Advanced Research
Projects Agency (ARPA). ARPANET (as the Internet was originally called) had only
four nodes on it and sent its first message in 1969. Today's Internet has millions of nodes
on thousands of networks. A network is a collection of two or more computers that are
connected to share resources and information. Today, high-, medium-, and low-speed data
lines connect networks. These data lines allow data (including text, graphical images, and
audio and video data) to move from one computer to another. The Internet backbone is
a collection of high-speed data lines that connect major computer systems located around
the world. An Internet service provider ( ISP ) is a company that has a permanent con-
nection to the Internet backbone. ISPs utilize high- or medium-speed data lines to allow
individuals and companies to connect to the backbone for access to the Internet. An Internet
connection at home generally is a DSL or cable data line that connects to an ISP.
Millions of people in most countries around the world connect to the Internet
using computers in their homes, offices, schools, and public locations such as libraries.
In fact, the Internet was designed to be a place in which people could share information
or collaborate. Users with computers connected to the Internet can access a variety of
services, including e-mail, social networking, and the World Wide Web where they can
find a variety of information at many different types of Web sites (Figure 1-2).
Figure 1-2 The Internet makes available a variety of services such as the World Wide Web.
What Is the World Wide Web?
Many people use the terms “Internet” and “World Wide Web” interchangeably, but that
is not accurate. The Internet is the infrastructure, the physical networks of computers.
The World Wide Web , also called the Web , is the part of the Internet that supports