Perhaps you're a casual user of the Internet, occasionally surfing the Web and exchanging e-mail. Perhaps you've published your own Web page and spend several hours a day online reading the latest news, checking stock quotes, buying groceries, doing research for a paper, or playing computer games. Regardless of your experience with the Internet, your future will be affected by its existence.

The Internet is a worldwide network of computer networks linked together through high-speed, high-volume telephone lines and cables. You can use it to talk to someone in India, buy salsa from someone in Texas, check the status of your stock portfolio, learn about colon cancer, and chat with a group of people about your common interest in rap music.

Today's Internet bears little resemblance to its beginnings. In 1958, Russia launched Sputnik, and the Cold War was in full swing. Soon after, the Advanced Research Projects Agency (ARPA) was created by the U.S. Department of Defense to help the United States regain and maintain a lead in technology. The Department of Defense wanted a comprehensive, indestructible network that could communicate even when under enemy attack. If one of the computer links was destroyed, messages still had to be able to get through to their destination. With this in mind, packet switching was developed in 1968. Within a message (packet) was information about its destination and how to get there so that, if the message hit a point of failure in its route, it could tell where it needed to go next to reach its final destination.

In 1969, using packet switching, ARPA created an internetwork (a network of networks) called ARPANET. There was still a problem, however. How could they get different types of networks to communicate with one another? The U.S. military wanted to link all its networks together worldwide. Despite its inability to link these different networks together, the ARPANET grew. Military and defense contractors, universities, and scientists were rapidly getting connected to this internetwork. Throughout the 1970s and 1980s, different portions of ARPANET were declassified and opened up to the public. The first public demonstration of ARPANET occurred in 1972, and other organizations began asking permission to connect their networks to it. In 1983, a new protocol (the way computers talk to each other) called Transmission Control Protocol/Internet Protocol (TCP/IP) was integrated into ARPANET and the all-inclusive network finally was realized. Many Internet historians cite ARPANET's switching over to TCP/IP as the birth of the Internet.

In 1986, the National Science Foundation began NSFNET, a much faster network than ARPANET, which connected five supercomputing centers at Princeton, Pittsburgh, the University of California-San Diego, the University of Illinois at Urbana-Champaign, and Cornell. The purpose was to connect major researchers and scientists around the globe. This original group quickly grew to include more universities and some corporations and industrial institutions, including the National Aeronautics and Space Administration. Soon, e-mail, file transfer, and newsgroups became commonplace. By 1990, due to a newer, faster NSFNET, ARPANET was disbanded and commercial (business for profit) use was permitted on NSFNET.

Because NSFNET was largely funded through federal grants, the network was becoming too costly for the U.S. government. So by 1993, commercial firms stepped in and provided faster and higher capacity transmission, and the Internet became more efficient. The lines put in place by this faster network became the backbone (the main arteries of the Internet where the largest volume of messaging traffic travels) for today's Net. NSFNET was shut down in 1995 because the Internet had grown to assume all of NSFNET's abilities and more.

ARPANET and NSFNET were based in the United States, but at the same time they were being developed, other networks were popping up in different regions across the globe. For example, the EBONE was created in 1991 as a group of European organizations coordinated their efforts to form their own internetwork. EBONE soon plugged into the U.S. Internet backbone and suddenly Europe and the United States were linked together. This has happened worldwide to such an extent that today every country on every continent has Internet access.

The World Wide Web was the brainchild of physicist Tim Berners-Lee, who developed a way to organize information in a more logical fashion by using hypertext to link portions of documents to one another. Although Berners-Lee formed his idea of the Web in 1989, it was another four years before the first Web browser (Mosaic) made it possible for people to navigate the Web simply.

No one person or organization is in charge of the Internet and what's on it. Various organizations take part in its administration. For example, the Internet Corporation of Assigned Names and Numbers (ICANN), a nonprofit, private corporation, is responsible for coordinating the assignment of Internet domain names, IP address numbers, and protocol parameter and port numbers. As part of this work, ICANN accredits registrars offering .com, .net, .org, .biz, and other top-level domain names. The Internet Society, a nonprofit, nongovernmental, and international organization, works to maintain the global viability of the Internet by focusing on technical standards, public policies, and education and training. The World Wide Web Consortium (W3C) promotes the development of common protocols to ensure global usability of the Web. None of these, however, actually control the Internet. The Internet runs all by itself, almost as if it were a living thing.

The Internet might have begun as a project by an agency of the U.S. government, but there is no regulation or censorship of it today by any governmental agency. Users who find questionable content on the Internet can only contact the local administrator of that site or resource and air their complaint. Of course, people who break local laws by the content they post online or their activities on the Internet are liable for prosecution. Laws governing Internet activities are evolving, especially where they relate to bullying, harassment, privacy, and security of personal information.

Since its invention, the Internet has become an essential part of the contemporary world. It offers a variety of resources to business and individuals and is utilized in nearly every form of administration and commerce. It has revolutionized traditional media and enabled seamless, immediate communication worldwide. As more and more users adopt mobile computing through the use of smartphones and tablets, Internet priorities, products, and services have changed to meet demand and take advantage of new technology, and they will continue to do so in the future.