When people create websites, there are what people call 'Markup Language' that allow people to mark up and create websites. Most of the time, the websites people see on the internet are consisted mainly of "HyperText Markup Language", and "Cascading Style Sheets".
HyperText Markup Language (HTML)As the book called 'Engineering Long-Lasting Software' says,
If the Web browser is the universal client, HTML, the HyperText Markup Language, is the universal language. A markup language combines text with markup (annotations about the text) in a way that makes it easy to syntactically distinguish the two.
HTML is the most famous Markup language nowadays and is fairly easy to get used to it. I personally found it interesting while I was learning it since as I type, the screen displays it, and it is just amazing experience to see how technology allows us to do that. HTML 5 is the newest type of HTML and it is used mostly for having interactive functionality for websites and more for games.
Cascading Style Sheets (CSS)
The book called 'Engineering Long-Lasting Software' also mentions about CSS:
CSS allows people to 'decorate' the contents of HTML so that people will enjoy seeing and reading your contents on the web. As the next screencast shows, the CSS (Cascading Style Sheets) standard allows us to associate visual “styling” instructions with HTML elements by using the elements’ classes and IDs.
I personally found it interesting to learn both HTML and CSS at codecademy as HTML is fairly easy language to learn compared to others, and you can enjoy how things you type change the decoration of your web page by playing around with CSS.
Thus, I strongly recommend that those people who are interested in webs and other things start learning at codecademy. It is very fascinating and definitely worth trying!