1. A computer-implemented method for automatically sending a campaign message to a recipient at a recipient computer, comprising: determining, by a sender server, that the recipient is eligible to receive a campaign message corresponding to an active campaign; obtaining a campaign score for the active campaign based on a measured performance of the active campaign over time, wherein the measured performance is derived from consideration of both a revenue received by the active campaign on a per campaign message basis and a number of purchases per campaign message, wherein each campaign message of the active campaign has been sent to a plurality of recipients; determining that said campaign score for the active campaign is the highest among campaign scores for active campaigns from which the recipient is eligible to receive campaign messages; and automatically selecting and sending, by the sender server, a campaign message corresponding to the active campaign to the recipient computer.