Concerns over digital integrity -- the reliability, transparency, and trustworthiness of online information and communication -- have grown amid rising challenges posed by deceptive content, opaque platform designs, and rapidly evolving technologies. Whether our generation can sustain an open and trustworthy online space now depends on how we respond to these unprecedented challenges. This dissertation investigates how collective efforts by ordinary users have responded to the worsening state of digital integrity in online spaces. First, I compare a crowdsourced fact-checking community in Taiwan with professional fact-checking organizations, evaluating their contributions across four dimensions: variety, velocity, veracity, and viability. The study shows that crowdsourced fact-checking serves as a valuable complement to professional efforts and even holds distinct advantages in some respects, particularly in variety and velocity. Second, I analyze open records from Weibo’s community-driven content moderation system to examine how various stakeholders collectively shaped an experimental model of platform governance in China. The study highlights the platform’s strategic approach to handling socially sensitive cases and reveals how users, acting as reporters and jurors, participated in the system with various motivations. Third, I conduct a large-scale quantitative analysis of Chinese algospeak by extracting captions from social media videos and using AI to detect systematically altered terms. This study shows how content creators strategically modify terms across different topics to balance content reach, monetization goals, and the evasion of perceived moderation, which reflects a broader distrust in platform algorithms and governance. Taken together, the studies in this dissertation characterize users not as passive victims of a deteriorating information ecosystem, but as active participants who work to correct or adapt to undesirable information environments, offering multidimensional insights into how collective engagement can help preserve digital integrity online.