advertiser vs promoter

advertiser and promoter both are nouns.

Word	Noun	Adjective	Verb	Adverb
advertiser	Yes	No	No	No
promoter	Yes	No	No	No

As nouns, promoter is a hyponym of advertiser; that is, promoter is a word with a more specific, narrower meaning than advertiser:

Other hyponyms of advertiser include huckster, booster, plugger, tout, touter.

advertiser (noun)	promoter (noun)
someone whose business is advertising	someone who is an active supporter and advocate
	a sponsor who books and stages public entertainments