Introduction Current research investigated whether emotionality of content would facilitate the possibility to share information on social media by using event-related potentials. Theoretical development Emotionality is an excitatory state which evokes autonomic nervous system. Previous studies suggested that stimuli with high emotionality elicited increased P100/P200 amplitudes relative to stimuli with low emotionality (Huang & Luo, 2006). Research design We tested the purpose in an affective priming paradigm in which participants were exposed to online content (i.e. the "prime" stimulus) followed by a stimulus (i.e. the "target" stimuli) from International Affective Picture System. Participants were required to judge whether the target was neutral white picture. Next, a nine-point Likert scale was followed to assess the level of emotionality for online content. Result and conclusion We observed a congruency effect in the priming effect. More importantly, early brain potentials P100/P200 were higher when participants were exposed to online content with more possibility to share than online content with less possibility to share. This finding could be explained by the "response level account" theory (Fazio, 2001). This study provides an insight to neural mechanism underlying emotionality of online content.