An optimization tool is provided for individual participants who participate in multiple online advertising environments wherein the tool interfaces with the multiple environments in an optimal manner on behalf of the individual participants. A participant using the tool can specify goals and/or constraints for participating in one or more of the networks, and then the tool automatically optimizes advertising expenditure for advertising transactions across the different networks. The tool also tracks the performance of the participant across the different networks and dynamically tunes the participant's advertising expenditure based on such performance as well as the changing conditions of the marketplace.