Introduction

The Internet is a global collection of more than 75 million computers (and growing) linked together to share information. The Internet's physical structure includes telephone lines, cables, satellites , and other telecommunications media. Using the Internet, computer users can share many types of information, including text, graphics, sounds, videos , and computer programs. The World Wide Web (also known as the Web or www) is a part of the Internet that consists of Web sites located on different computers around the world.

History of the Internet and the World Wide Web

The Internet has its roots in the Advanced Research Projects Agency Network (ARPANET), which the United States Department of Defense started in 1969. In 1986, the National Science Foundation formed NSFNET, which replaced ARPANET. NSFNET expanded the foundation of the U.S. portion of the Internet with high-speed, long-distance data lines. In 1991, the U.S. Congress expanded the capacity and speed of the Internet further and opened it to commercial use. The Internet is now accessible in almost every country in the world. The World Wide Web was developed in Switzerland in 1991 to make finding documents on the Internet easier. Software programs designed to access the Web, known as Web browsers, use point-and-click interfaces. The first such Web browser, Mosaic, was introduced at the University of Illinois in 1993. Since the release of Mosaic, Microsoft Internet Explorer and Netscape have become the two most popular Web browsers.