Social-media-based diaries in qualitative longitudinal research: opportunities, challenges, and design principles

As society becomes increasingly digital, mobile, and always connected, qualitative longitudinal research (QLR) needs methods that resonate with everyday practice and trace change as it unfolds. This paper examines social-media-based diaries (SMBDs) within WeChat Moments in a 17-week study of 82 first-year Chinese undergraduates transitioning to university. SMBDs amplify core strengths of diary methods (immediacy, multimodality, contextual richness), yielding layered archives that render trajectories visible rather than isolated moments, while embedding documentation in participants’ routines mitigates attrition and reactivity. Yet platform logics introduce trade-offs: fewer opportunities for sustained reflection, greater fragmentation, reduced researcher scope to guide focus, and audience-shaped self-presentation in semi-closed networks. We propose transferable principles: align SMBDs with participants’ digital habits; scaffold in-situ expression and reflective insight; respect participant-controlled visibility; maintain minimal researcher presence; and archive iteratively. We argue for adaptive digital methodologies that work with platform affordances while navigating ethical and cultural complexities.