Abstract: As the amount of user-generated content grows, an increasing number of users start to delete previous posts. Information deletion in social media is not only a personal information management behavior for social media users but also has an impact on the development of social platforms content resources. Based on self-awareness theory and the perspectives of defense acquisition information management, this study investigates the motivations behind the deletion behavior of WeChat users' moments. The results of Structural Equation Modeling demonstrate that information security, field environment, and content value of defensive management have a significantly positive influence on information deletion behavior, and that the level of self-disclosure plays a mediating role in the relationships between information security, information value, and social media information deletion behavior. The research contributes to a comprehensive understanding of social media users' usage paradigm and provides decision support for the utilization of social media data and economic development of platforms.

Key words: Social media, Social dynamics, Information deletion, Behavior motivation, Information management