Simply put, the internet is a utility. It is made up of a very large number of  computers that are hooked up to one another into a large network. This Network is so large, it's called the World Wide Web, or "The Web" for short. As with most things concerning The Web, it also has other popular and / or slang names, and is also known as "The Net", The "WWW",  The "Information Super Highway", The "Cyber World", "Cyber Space", and "Virtual Life", to name a few. 

Getting on the Internet, or getting hooked into to the Internet, (which is a more accurate description) is most often referred to as going "On-Line", or getting "Plugged I", but it is referred to in many different ways, also. There are plentiful slang expressions that vary greatly from culture to culture, and sub-culture to sub-culture, and if you hang with that group that says 'BAD" when you mean "GOOD" and "COOL" when you mean "HOT, you are likely to refer to going on-line as getting "REAL" when you mean "VIRTUAL".

Yes! Consider some other Utilities... let's say, the Gas Company. It has a network of pipes, or lines, that hook up many homes and businesses. It supplies a useful service which most use for heat, air conditioning, or cooking, but has other uses also. In their network the gas only flows one way, so the network has strong limitations.

Consider the Electric Company. They have a network too, but the capabilities of their network are a little expanded. It is a two way network. It is a little known fact that if you manufacture electricity on your property, the electric company has to buy it from you. But since most people don't have windmills, waterfalls, or refined uranium, that produces excess electricity, you can see why it is a little know fact.

When you consider the telephone company, you begin to get closer to understanding the Internet. It is definitely a two way network - you can talk (send) as well as listen (receive). You can use the network for other things also - you can FAX, for example. You can conduct business, buy things, sell things, get information, and even access the Internet.

The telephone network is made up of a number of different companies, AT&T, Bell, US West, to mane a few. If you use AT&T, when you make a call to someone who uses a the Bell Southwest company, the call goes through because all the different phone networks are hooked together forming a larger network. And all the networks in this country have connections to networks in other country forming an even lager network. But the network still has limitations. It's hard to see live video over your phone, for instance. 

The Internet is a utility also. It has a much vaster network than the phone network, because all the phone companies all over the world are actually part of the Internet - If they like it or not. And some phone companies don't like it because they feel that the Internet utilizes too much of their line space. But that is a different story.

Many computers on the Internet network connect to one another by phone line, but there are other ways that the Internet's computers connect to each other, also. There are dedicated Fiber Optic lines, Cable Television lines, LANs (Large Area Networks) Company Intra Nets, Satellites, Direct Connections, etc. This networks of computers all over the world, made up of all these different smaller networks, is what makes the Internet the "World Wide Web".

Each time you go "on-line" and "plug in" to the Internet by dialing a number on your phone line, or connect through your TV cable, you have instantaneous world wide access to every other part of the Internet. And who does that include? Well, almost half the homes in the US, all country governments throughout the word, as well as almost all State County, and local governments, almost every successful business in the world, all elementary schools, middle schools, high schools, colleges, college students, and that's just the beginning. 

For a more comprehensive look at who's on-line, see  What Can You Do On The World Wide Web?