This study provides a comprehensive meta-analysis of 47 quantitative articles (2014–2024) to synthesize these divergent results. The novelty of this research lies in its rigorous application of the DerSimonian-Laird random effects model to navigate an exceptionally high level of residual heterogeneity (I² = 99.998%), offering a more statistically robust generalization than previous fixed-effects syntheses. The results demonstrate that herd behavior exerts a significant positive influence on behavioral intentions (intercept 0.399, p < 0.001), particularly in emotional or high-risk decision-making contexts such as purchase and continuous usage intentions. The originality of this work further extends to its subgroup and moderation analysis, which identifies that the "herding effect" is not uniform; its strength is critically contingent upon contextual moderators, specifically socio-cultural dimensions (collectivism vs. individualism) and the type of media platform utilized. These findings bridge the gap between Herd Behavior Theory and the Theory of Planned Behavior (TPB) by positioning herding as a dominant subjective norm. The study concludes that understanding individual decision-making in the digital age requires a nuanced consideration of these moderating factors to account for the complexity of social influence.