This research explores the relationship between social media and mortality, focusing on social media as a thanatosensitive technology that promotes death preparation and commemoration. Employing concepts from the Value-Sensitive Design approach, our research identifies three main stakeholders surrounding the online commemoration experience. As an exploratory study, we conducted in-depth interviews and observations (n = 9) to better understand key stakeholders’ experiences in online and offline commemorations. After analyzing the qualitative data, we extracted design requirements that were used to create a conceptual commemorative system and a functioning prototype. An informal user testing (n = 6) yielded positive feedbacks on the new system for it offers the unique opportunity to reflect existence, prepare for death, and create a community of commemoration that helps memorialize the deceased and recover from grief. The study suggests that commemoration via social media aids in maintaining user volition, induces active and interactive participation, and allows for a continuation of the digital legacy. Such findings may help deepen the understanding of humans’ perception of death and commemoration within the context of social media.