Think of the Internet as millions of computers that can talk and share information. What kinds of computers? Everything from the lowliest 286s and Apple IIes to sophisticated workstations running UNIX, NT, Windows and other hot operating systems. What kinds of information? Well, correspondence certainly (a.k.a. e-mail), but more than just that. Graphics and video clips are making digital trip every second of the day, as are Supreme Court decisions, the latest jokes, news, market reports, latest games and lots, lots more. 
The Internet is run by the people who are on it. That means you and me! We all have a responsibility to ensure that the Internet is used in positive ways. New people are coming online every minute now. That's a lot of people, a lot of new ideas, a lot of potential.

How many host computers are hooked up to the Internet? Put simply, the Internet allows millions of people around the world to communicate and share (A lot huh!). New Internet addresses continue to be added all the time. Keeping up with the changing/growing character of the Internet is a bit like trying to count raindrops (ever try?). They just keep coming and coming. 
These host computers are located in libraries, universities, governmental and corporate agencies, and elementary, middle and high schools all over the world. They're connected by high-speed phone lines. It takes as little as 640 milliseconds for a message to travel from North America to Antarctica.

It all started with Arpanet. The military of the United States created Arpanet in the 1970s to scatter their computers so that no single nuclear bomb could wipe out their computing capabilities. The network evolved and spread to other organization, especially universities and libraries. Eventually, a more generic name was adopted: the Internet.