If I catch you spamming your business in my comments section, I am allowed to use any means I deem fit to link your business to extreme bestiality, human trafficking, or frankly anything that I find amusing. Posting an advertisement in my comments section will be as considered consent to said practice.
Note: Linking to a site/business that is somehow related to the post/discussion thread is fine. Filing in the Website portion of the user form with your own personal site is fine. Asking for a plug if you are a regular is fine. Spam is not.