wheel - 5:33 pm on Dec 2, 2010 (gmt 0)
Typically they aren't trying to make 1 sale per coupon.... they are hoping to make 1 repeat customer per coupon.
I'm not ecommerce anymore, but the idea of repeat customers is a given in my industry. In fact it's common to build up a large client base then basically retire. Once someone has some many thousands of clients in my business, the repeat business is steady enough to live off of with no further advertising or promotion.
Despite the fact that I make money from each sale, there's definitely a long term value as well to each client.