Eff'nhell, National...

[king1]

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...

So a link to a business website is OK?  That isn't considered advertising?

From the rules:

Any posts deemed to be advertising or promoting any political party will be removed

you are confusing post content with the users signature