Combining Historical CTR and Bid Amount in Search Message Selection

A method, system and computer readable medium selects additional message content to display to a user when the user request base content. In order to optimize the intermediate selection pool of message candidates (from which a final selection is chosen), for each candidate message, a historical aggregate of CTR data is combined with an offline estimate, also obtained from historical data, of RElative Probability of Action (REPA, which combines computed relevancy scores and ranking information) and with bid amount to obtain an estimate for revenue generation. This estimate is combined with dynamic matching between the message and the page/user pair to obtain a final score for each message that is used to create the intermediate selection pool of message for the page displayed. Final message selection uses a feedback loop, using specific CRT in conjunction with the specific page displayed, for the messages in the intermediately selected pool.