Amid the pandemic of coronavirus diseases, virtual conferences have become an alternative way to maintain the prosperity of the research community. This study investigated attendees' participatory behavior in a virtual academic conference (TWELF2020, Taiwan) and studied the interrelationship among their mastery experience, competence, and engagement to shed light on the development of virtual conferences. Data were collected based on 602 unique IDs via their unstructured trace data and 106 respondents to the post-conference questionnaire. Ten indices were derived from participants' unstructured log to describe the conference-based and session-based behaviors. Study results demonstrated that virtual conferences could facilitate the extended and deepened participation of the research community, nourish the participant-centered scholarship building, and create an engaging conference environment that reflects quality experiences regarding participants' mastery experience, competence, and engagement. The implications of the study can inform future virtual conference organization to provide more engaging and rewarding conference experiences for participants of all gender and academic ranks.