Online communities are extremely popular; yet most of them still rely primarily on text for knowledge creation and communication. This paper describes a graphical webpoll prototype-a mix of information, knowledge, and social visualization-that has been designed and deployed in an online discussion board on herbal antidepressants. The prototype, hereby named the "plot-poll", allows users to collaboratively construct a sequence of mini histograms that indicate experienced mood change during a ten week period. The pilot study shows that plot-polling is quite effective in engaging low-frequency contributors to participate. More work is required to support these findings, and reveal whether the graphic format is able to provide affective qualities to the user experience.