As we explained in our What is the Internet and History of the Internet articles, the Internet is a collection of interconnected computers and computer networks that allows information to travel between any number of connected points. It works because all networks have adopted a free-form way of transmitting information (packet switching) and a standard way to communicate with each other (TCP/IP). This article will get a bit more into detail about how the Internet works for you as an individual user.
Connecting to the Internet
To connect to the Internet, your computer must be connected to a modem, either through a cable or a wireless radio signal. Short for "modulator-demodulator", a modem converts information from your computer into a signal that can travel along the Internet, and in turn can convert incoming Internet signals into information that your computer can understand. Many modems are provided by Internet service providers (ISPs), telecommunications companies that provide Internet connectivity. Common ISPs include AT&T, Comcast, Time Warner Cable, and Verizon.
When you connect to the Internet, your computer is given a unique number that helps identify it out of all of the other things on the Internet. This number comes in the form (X . X . X . X), where each "X" is a number between 0 and 255. This is called your Internet Protocol address (or I.P. address).
Connecting to another point on the Internet
When you want something from the Internet, whether it's to download a file, look at a web page, or just talk to somebody else, you need to connect to that point. When you're initiating a request to connect to a point on the Internet, that makes your computer the "client", and it makes the other point the "server" (or sometimes "host"). Points in-between that direct how communication flows back and forth between the two points (remember, with packet switching, information can take multiple paths on the Internet) are called "nodes".
For one thing, you need to know how you want to connect to a point on the Internet. We mentioned that all Internet networks use TCP/IP as a standard, but there are sub-protocols that denote certain actions that you want to take over the Internet. For example, as we discussed briefly in some of our previous articles, common sub-protocols include HTTP ("hypertext transfer protocol", for when you want to view a web page on the World Wide Web), VoIP ("voice over Internet protocol", for when you want to make a phone call over the Internet), and FTP ("file transfer protocol", when you want to move computer files back and forth between two computers on the Internet).
Many services that use these protocols are designed to take care of the heavy lifting for you; for example, many web browsers allow you to type in "www.example.com" without the "http://" bit, and they will fill the protocol in automatically for you.
For another thing, you need to know where you want to connect to on the Internet. For example, if you want to connect to a specific computer, you need to know that computer's I.P. address. Or, if you want to view a web page on the World Wide Web, you need to know that web page's U.R.L. address (see our What is a URL article for more information).
Again, many services can help take care of the hard part for you. For example, search engines can help you find the URL for a specific web page by displaying the content that's there. Also, many email and VoIP services have an email address or user name stand in for an I.P. address, which makes finding a specific person much easier to understand for you as a human!
That's a brief explanation of how the Internet works when you use it!