Abstract: The present invention relates to a computerized engine and method for using the same to determine and effect product sales to customers based on customer-driven affinities relating to the products. In some embodiments, the computerized engine includes hardware and software and uses customer or transaction data or product characteristics to calculate an output relating to the affinity. In some embodiments, the computerized engine provides an output indicative of the affinity. In some embodiments, the computerized engine is coupled to a database containing the customer or transaction data or product characteristics. The system and method can also determine a reduced affinity depending on a period of time elapsed between a pair of events being related, or as a function of the age of collected affinity data.