Communicating About and Through Platform Values: Legitimizing Public Expression Regulation on X and Weibo 2007–2024

In this article, we argue that social media platforms communicate their governance strategies both about and through values across diverse sites of communication— about values in presenting normative ideals and through values to justify their content moderation practices. Moreover, we highlight the significance of analyzing platform values across temporal and regional contexts, especially beyond the Western sphere. Focusing on X and Weibo, we employed content and network analysis to examine how they articulated values in different venues to regulate public expression from 2007 to 2024. Our findings reveal an increasing convergence in how the two platforms communicate about values in their community guidelines, suggesting a trend of institutional isomorphism in response to shared challenges such as misinformation and online safety. However, they diverged in communicating through values in administrative posts. While X emphasized personal-level values such as self-expression, Weibo prioritized social-level values, particularly social and political security, often in the context of addressing concrete cases.