An internet project

I like to use my blog to crowdsource things.  I don't have that large of a readership  but sometimes you are extremely helpful.  So this is another post where I ask you to give me suggestions and ideas. I am currently teaching Basic Computers at CBC.  At the first class I asked the students to rate themselves from 1-10 in computer knowledge, with 1 meaning, "I can barely turn a computer on," and 10 meaning "I should be teaching this class."  Most of them were a 2.

So I began with vocabulary. After learning much of the computer lexicon, I decided to turn my attention to using the internet.  There are 2 reasons for this strategy.  One, almost anything you can do with a  computer can be done online.  And two, it seems to me the trend is toward cloud computing.  I think the proliferation of netbooks demonstrates that we will soon to be mostly a world of terminals where the real computing is done on a server and the browser is the most important piece of software.

Here is where I ask for your help. What are the absolute must-knows of the internet?  I am composing a project in which I assign them a variety of tasks.  What do you think everyone should know about, or know how to do on, the internet?

BTW: I refuse to add "Learn to play Farm Town" to the list