Teaching kids their first lesson on the WWW is wonderful. At that stage, the main point I always want to communicate is the fact that the WWW is completely democratic. (because I believe that one of the most important skills a child now needs to survive is the ability to discriminate...more on that another time.) I tell them that there is nothing to stop me creating a web site that says the moon is made of cream cheese. I also tell them that if they copy out that web site and hand it in, they will fail their GCSEs.
'Who do you think is in charge of the Internet?'
'I know! Bill Gates!'
'Isn't it The Americans?'
... and one glorious time...
'Is it you, Miss?'
On the other hand, teaching 18 year olds TCP/IP and the concept of URLs and DNSs, the problem is that they have no sense of wonder. The fact that I can type a line from a (much underrated) Britney Spears song into Google, and in less than a second I have the complete lyrics of that song on my screen... the elegance of all those servers acting together... the trillions of packets all colliding and whizzing across the Net...
'Your problem is that you are just not impressed enough with the Internet!'
Actually, the problem is slightly subtler; they all believe that the world of computers is made up of millions of other teenagers all of whom have PCs running identical MS products that are joined together by wires known as the Internet. When you think about it like that, the fact that they all communicate perfectly is not much more impressive than computers themselves, and heaven knows they've lost their sense of wonder there.
On a slight tangent, here's a common exam question...
'A company upgrades its network so that all the employees can send and receive e-mail. State three concerns that the management might have'
It's galling how many teenagers simply answer 'He would be worried that his staff would send e-mails when they should be working'
And that's not because they are making a subtle comment on the tyranny of the e-mail in the modern workplace, it's simply because they don't admit the possibility of an e-mail being used for work. E-mail, by definition, is recreational.