Eff'nhell, National...

[king1]

A troll! You don't say

Isn't there a rule here that says there should be no advertising?

The no advertising/spam rules (2.c. and 2.i.) apply to post spamming, for obvious reasons...
For signatures a simple text link is fine - Rule 5 - "reasonable size and does not contains images ... maximum two lines ".
That might get reviewed if anyone started putting up paragraphs of advertising blurb in the signature, but there is a character limit in signatures...