This is the kind of marketing but its related to affiliate marketing. Let me quickly describe it. Back end marketing or back end affiliate marketing is that where customer is served the second product after buying the first product.
The back end affiliate marketing has been in existence for quite a while now and it’s even successful on most of the occasions. The reason for success is the first relation developed between the buyer and seller therefore to sell again to the same customer is not a difficult task, keeping in mind that you have the kind of products, which could make the customer interested in your products.
This is a win-win situation for both the affiliate marketer and the merchant because affiliate has made the effort to bring the buying customer to the merchant website and merchant has the benefit that his products could sale at a faster rate.
Affiliate in other sense enjoys some extra commission. So, just look at the merchants who promote the Back end marketing trick.