Web Hosting : Hostname

Q. Can somebody explain the WHM Hostname feature? I am a bit at loss here as the instructions in WHM say that I should use a hostname that I “will not be using for any account”. Does that mean that I should not use my regular domain name?
E.g. if the server’s main website will be example.com (i.e. I will need a example.com account, won’t I?), should I use a random hostname that has not DNS registry? Or should I use something like host.example.com?

Ans: You will want to use the suggested format, such as

When you set this hostname, plan for expansion incase you add more servers in the future. So might not be such a great idea.

EDIT: And in answer to the “my domain name” thing, you will want to use the main domain on the box. For example, we have pfXX.abc123.com, with X representing the server number.