15. The method of claim 9 , further comprising: classifying the merchants into merchant categories based on: item tiers of items sold by the merchants; mean item prices of the items sold by the merchants; and item volumes of the items sold by the merchants.
16. The method of claim 15 , further comprising: classifying the customers into customer categories based on: item tiers of items purchased by the customers; mean item prices of the items purchased by the customers; and item volumes of the items purchased by the customers.