Tandem electro-optic devices and active materials for electro-optic devices are disclosed. A fluid flow path is disposed between the pump and the motor. The board is composed of at least 40-50% of the coconut mesocarp fibers. In addition, the appliance may separately track the transaction activities of end users who receive recommendation messages and the transaction activities of end users who do not receive recommendation messages, so that a comparison of the effectiveness of the recommendations may efficiently be demonstrated without requiring any modification to the code or architecture of the web server.