Wayne,
Affiliate marketing is another form of marketing. The so called superdupercasino becomes superdupercasino because they have a good mix of paid up front marketing and affiliate marketing.
Branding on the internet unlike other media’s is easier to credit those who bring in the sale. In some cases a cookie is dropped on the persons PC so should they not make a sale on their first visit, it is credited when the customer revisits.
Other marketing forms affiliates partake in is pay per impression (even though this is getting outdated it is still used) and credits the affiliate everytime someone visits their website and their banner is displayed.
Affiliate marketing is not for the faint hearted and in many cases is a golden opportunity for many to make tons of money who have no or little marketing background.