The profound impact of the Internet is only a shadow of what's to come. But if you understand how the Internet works now, you can use it to your advantage in the future.

A generation ago, the prominence of the Internet was unimaginable, even by science fiction writers. Today, the extensive changes to our society brought about by the Internet are far from complete. E-commerce and other hot applications are exploding, and new applications continue to emerge right behind them. Inevitably, the Internet will eventually combine with (or possibly overrun) the telephone and cable TV industries.

You may wonder how it all began. A few programmers at the Department of Defense started the ball rolling. Next, new communication technologies made expansion possible, and independent student programmers in Illinois and Sweden turned the Internet into what it is today. As a wide-open frontier, the Internet is the Wild West of information. Governments want to tax and regulate it, but can't figure out how. Reporters dig for horror stories, but find few.

So, what is the Internet? Try to picture tens of thousands of computers linked by tens of thousands of fiber optic lines. AT&T, Sprint, MCI, UUNet, and other companies own the communication lines and sell access to them. Computer centers buy this access, and provide services that connect millions of businesses, universities, and individual homes and offices to those millions of computers, via a variety of data lines, including regular telephone lines.

No one owns the Internet, but each piece has an owner. However, no one piece is necessary for the entire system to operate. The Internet itself has no long-distance charges, no online charges, and no dues. The people who connect you to the Internet charge for access (i.e. CompuServe, AOL, Prodigy, MindSpring, and others). In turn, the owners of the main communication lines charge these companies for access to the network. But once you get into the Internet, there are no further charges (unless of course you choose to buy something or subscribe to an additional service).

With this, there are no preset paths for communications on the Internet. No switches connect your computer to another computer. No central brain controls it.

When you send an Internet message, your computer begins the message with an electronic address. When your message reaches the next junction point, the machine there (a router) reads the message, identifies the best path toward that destination, and sends it along. When your message reaches the next crossroad, the same thing happens. Your message may hit five or 10 crossroads before it gets to its destination. And when your friend on the other end replies to your message, his or her message will probably come back to you along a different path. As long as the addresses are valid, the messages will get to their destination.

The Internet provides countless paths for messages to take. A message between New York and Chicago may travel by way of Montreal, Salt Lake City, and Dallas. Many times, a message from one U.S. city to another makes its way through Europe first. This makes the Internet nearly "bombproof." Routing makes no difference to either sender or recipient. The route a message takes depends on how busy the various links are. Traffic follows the least busy path, with little regard to distance.

Now you can see why we call the Internet a routed network. The telephone system, on the other hand, is a switched network.

Is the Internet the same as the Web? Almost. The Internet refers to the physical connection between computer networks all over the world. The World Wide Web is not a separate set of connections. The Web is simply a special method of sending information over the Internet. There is no physical difference between the Internet and the Web. However, they do differ in terms of communication protocol.

We base Web communications on the hypertext transfer protocol (http), which makes it easy for users to interact with the network and share graphic files with each other. All Web addresses (also called URLs, or Universal Resource Locators) begin with "http." The special hypertext communication language allows you to browse easily through files on another computer by clicking on the filename. The hypertext system allows people to establish their own site on the Web.

The importance of the Internet. For many users, the Internet has gone from just a hobby to serious commerce. In fact, most American companies today have at least one Web site. They use these sites in various ways (e.g., ordering, product information and support, and general business communications). Could electrical drawings and project proposals be far behind? In some cases, they aren't.

Looking back, e-mail (electronic mail) is what really made the Internet. In computer lingo, e-mail was the first "killer app" for business on the Internet. E-mail allows you to exchange messages with people at the convenience of all parties. You can send the same message effortlessly to any number of people, and transfer documents or computer files instantaneously.

How to use the Internet. The Internet allows you to communicate from office to customer to job site better than ever before. Think about how much time and effort you would save if you could get instant answers to site supervisors' questions on change orders, installation details, material delivery dates, and so on.

In today's fast-paced business world, most professionals are surprised if a business doesn't have a company Web site. They expect to reach you by e-mail and submit pay requests electronically. Your suppliers give you better pricing and/or service if you order electronically. Before long, almost anything that can be done online will be done online.

Sidebar: How It All Began

The Internet began in the early 1960s. The original purpose of the Internet was to serve the needs of researchers and the Pentagon, who decided they needed a communications system that could survive a nuclear holocaust. They proposed a new concept in system structure: the centerless network. This network would not consist of a typical hierarchical pyramid of systems arranged in a pecking order, but of an infinitely more flexible peer-to-peer interconnection in which no single system was in charge. Each element in the network was autonomous and independent.

That first network was "ARPANET." At universities, students learned how to use it for their own benefit. They told their friends about it, and started to share notes on topics that interested them. Then, their professors discovered how to take advantage of this, and began sharing research notes with each other. Thus, popular use of the Internet began with academics and adolescents, giving the Net much of its initial flavor.

The government decommissioned ARPANET in 1989, but many students and professors kept using it. Since that time, the leftover Internet has been growing by more than 10% per month!