A light-weight soft wing-sail for a wind-propelled vehicle includes a free standing rotating mast to be mounted in a vertical position on the vehicle and, three fully battened sail panels that together define the skin of the wing sail. The method or the system continuously monitors conversations in online forum, identifies trend of interest, identifies one or more content items that match the trend, and delivers the one or more content items to appropriate forum. The communications system may further include a receiving device for receiving the modulated signal from the transmitting device. One of the two reference pictures is temporally closer to the current picture to be coded.