What is "Warning level"?

[Ghost Nappa]

What's that Warning level thing? Mine is 0%. What is it used for?

[SERIOUSLY THOUGH*]

Basically, if someone dun goof'd, consequences can no longer be the same for that person and they get a warning.
It's to say "You've done something wrong, don't do that again." So, as the name suggests, it serves as a warning. They are accompanied by a message from mods/admin -- so you know what you've done wrong.
If your warning level goes above a certain %, some of your privileges may be taken away.

Example -
Ghost Nappa swears a lot defending his favourite game.
Mods get ruffled at such crass language and lay down a 10% warning.
Option 1 - Ghost Nappa realises how wrong he was and doesn't cuss any more. Warning eventually goes back down to 0%
Option 2 - Ghost Nappa starts swearing afresh and now posts nude pictures of himself.
Mods' jimmies can no longer get ironed out and they lay down more warnings that may be accompanied by a decrease of user privileges.
Kids cry. It's not a happy sight.

[Dutchtica*]

The kids crying is usually what gets me =/

[Lazlo Falconi]

Warning levels never really go down though. Most people forget they exist until someone makes a mod angry.