The World Wide Web is what you are looking at now - a combination of text and graphics presented on your screen using a browser. Web documents include hyperlinks which you can click on to jump to other web pages. These documents can also incorporate sound, animation, even full-blown applications.
Usenet or News is a public discussion system made up of forums known as news groups. Each one of these groups focuses on a specific topic or area of interest. Participants in a specific news group might have machine tools as their common interest, or an intense dislike of Barney the dinosaur.
Electronic Mail or e-mail is a system for sending messages from one computer to another.