Digital signage has been getting more popularity due to the recent development of underlying hardware technology and improvement in installing environments. Any signage is required to make its content more attractive to viewers by evaluating the current attractiveness on the fly, in order to deliver the message from the sender more effectively. However, most previous methods for signage require time to reflect the viewers' evaluations. In this paper, we present a novel, viewer-adaptive digital signage displaying academic conference posters, which automatically learns what structure and content are being attractive through the viewers' involuntary behaviors, and makes them more adapted to the viewers. This system takes away the current gap between viewers' evaluations and the content actually displayed on digital signage, and makes efficient mutual transmission of information between the cyber world and the reality.