The internet has provided us with the ability to see into other places of the world through video and imagery. It has also made it possible for friends and family to stay connected regardless of distance. This is the tip of the proverbial iceberg. How are all these services and experiences provided? Here is a much needed explanation for non-technical people out there.
In its purest form, the internet is simply a network of computers. The connections range from a simple wireless hub for use in a home or business place to massive cables that stretch thousands of miles on the seafloor. The physical structure of the internet is a massive topic. Let's focus on those computers for now.
There are two basic categories that a computer can fall into when using the internet. When you check your email, use a social site, or search on Google, your computer is called a client. A client makes requests and receives back output from the internet. When you enter in a search term, for instance, you are given back a page showing related sites and media associated with that search term. The second category is the server. The server provides the response to the request that the client made. Think of this simple analogy.
Client (you) "What is the weather in Las Vegas tomorrow at 4 PM"
Client has pressed "Submit"
Server(Google, Yahoo, Weather.com, etc.) "Sunny and Hot. Wind from the West."
Server has sent webpage about Las Vegas
Client has received webpage
Client "Oh, OK. Thanks"
As you can see the internet in a nutshell is a conversation between clients and servers. The process is far more complex than this. There are a few key technologies that allow for this conversation to take place.
There are three major facets that developers and designers of the the web talk about. The first is structure; how the web page is displayed in the browser. The second is presentation. This includes the typography, color scheme, and how the pictures, text, and videos render on the users' screens. The final piece of the puzzle is the data. The web would be nothing without information and data. Holding these three components together is program code. This acts as the glue that holds the whole system together. You don't see it but its there.
HTML is the main provider of basic structure for webpages. It is an acronym for Hyper Text Mark-up Language. The name pretty much describes what it is, a Mark-up language. It "marks-up" the components of the page so that they can be displayed to the user. It consists of a series of small pieces of code that contain elements of the text, video, links, and images. Nearly every part of a web page is found in the HTML structure. Think of HTML as the frame of a building; no decorative elements, just the bare bones of the walls, floors, and roof.
CSS aka Cascading Style Sheets is all about presentation. This piece of technology is used to make a page look good. All the decorations such as fancy text, image galleries, and attractive layouts are created by the CSS. The CSS is simply a series of rules that tells the browser how to display the HTML code. If HTML is the bare pieces of a building, CSS is the paint, furniture and carpet. CSS makes a site usable and good to look at.
The final part is the glue. Here complex computer code holds the whole thing together. If you have ever heard of the following, you are hearing about this "glue".
So there you go. We've covered the basics of how the internet can work. You can spend your whole life learning about all the details about these technologies. Go ahead! Its is very interesting and rewarding.