The following are images of internet warning signs in the halls of a South Korean grade school.  I grabbed them from this week's Frontline: Digital Nation. Well worth the watch.

This one says "Constantly playing computer games shrinks your capacity to think"

Here, "Slanderous comments on the internet hurts my friend"

And the popular slogan "Our ancestors were known as the politest Eastern state, now we are the kingdom of internet etiquette"

Finally, the young children sing the Internet Song!

Lyrics:

While chatting, first greet happily / Use polite words in a cordial way / During the game always be open, honest and do the right thing / Be careful on the keyboard / I know who did it (be careful) / I know I am the internet guardian angel / I will be the first to protect / I want to be the first to protect / Though faces are unknown, it's a warm neighborhood / Precious Internet friend / Precious Internet friend (friend!) / Netiquette!