19. In an electronic system for distributing promotional offers, a method of distributing limited quantities of promotional offers to a plurality of customers utilizing a transaction history database comprising an identification of transactions engaged in and an identification of products previously purchased by one or more customers, said method comprising: deriving a historical purchase probability profile from said transaction history database for at least a portion of the customers in said database and for a plurality of product groupings in said database, said historical purchase probability profile providing for each individual customer and for each individual product grouping a measure of the probability that said individual customer will purchase a product from said individual product grouping; for a customer included in said portion of the customers, applying a statistical model to said purchase probability profile to determine an estimated probability that said customer will purchase a product from said product groupings, said estimated probability being indicative of a likelihood said customer will purchase said product in comparison to all other customers included in said portion of customers; selecting, by a computing device in said electronic system, for distribution to said customer an offer associated with a product in said product groupings, wherein said selected offer is associated with a highest estimated probability that said customer will purchase said product in comparison to all other customers included in said portion of customers, determining whether said selected offer satisfies one or more constraints, wherein one of the one or more constraints is a limitation on a total quantity of promotional offers for said product that are distributable to all customers; and in response to said selected offer satisfying the one or more constraints, distributing the selected offer to said customer.
19. In an electronic system for distributing promotional offers, a method of distributing limited quantities of promotional offers to a plurality of customers utilizing a transaction history database comprising an identification of transactions engaged in and an identification of products previously purchased by one or more customers, said method comprising: deriving a historical purchase probability profile from said transaction history database for at least a portion of the customers in said database and for a plurality of product groupings in said database, said historical purchase probability profile providing for each individual customer and for each individual product grouping a measure of the probability that said individual customer will purchase a product from said individual product grouping; for a customer included in said portion of the customers, applying a statistical model to said purchase probability profile to determine an estimated probability that said customer will purchase a product from said product groupings, said estimated probability being indicative of a likelihood said customer will purchase said product in comparison to all other customers included in said portion of customers; selecting, by a computing device in said electronic system, for distribution to said customer an offer associated with a product in said product groupings, wherein said selected offer is associated with a highest estimated probability that said customer will purchase said product in comparison to all other customers included in said portion of customers, determining whether said selected offer satisfies one or more constraints, wherein one of the one or more constraints is a limitation on a total quantity of promotional offers for said product that are distributable to all customers; and in response to said selected offer satisfying the one or more constraints, distributing the selected offer to said customer. 21. The method of claim 19 wherein one or more of said product groupings includes one and only one product.