I asked my CS teacher why my institutions domain had only the www subdomain pointing to the webspace, but not also the second level domain itself. He then explained me that www is the *protocol* on the internet and it's necessary for the website to be accessible, and that pointing the SLD to the webspace in addition therefore wouldn't work.

How could I ever take him serious again? He's supposed to teach networking btw.

This job advert of an IT company would throw a compile-time error. Perfectly geared to the target group.