The present invention provides systems and methods for generating a highly targeted list of prospective customers for a list purchaser at least partially based on successful prospect lists previously used by the list purchaser, based on prospect lists used by related list purchasers, such as list purchasers in the same or similar industry as the list purchaser, based on previous customers of the list purchaser or based on any combination of this data. The systems and methods of the present invention are particularly suited to network-based prospect list services that provide prospect lists from a database to prospect list purchasers, such as direct marketers, over a computer network, such as the Internet. A system for implementing a computerized prospect list service includes a server computer hosting a prospect list service accessible via client computers to a plurality of list purchasers and a database of prospect lists. The prospect list service includes a user interface having controls for a list purchaser to access information concerning prospect lists stored in the database. The prospect list service is preferably available via a computer network to assist a first list purchaser in generating and accessing a list of prospective customers based on previously successful lists of prospective customers generated for the first list purchaser.