From politicians to podcast hosts, online platforms have systematically banned (``deplatformed'') influential users for breaking platform guidelines. Previous inquiries on the effectiveness of this intervention are inconclusive because 1) they consider only few deplatforming events; 2) they consider only overt engagement traces (e.g., likes and posts) but not passive engagement (e.g., views); 3) they do not consider all the potential places users impacted by the deplatforming event might migrate to. We address these limitations in a longitudinal, quasi-experimental study of 165 deplatforming events targeted at 101 influencers. We collect deplatforming events from Reddit posts and then manually curate the data, ensuring the correctness of a large dataset of deplatforming events. Then, we link these events to Google Trends and Wikipedia page views, platform-agnostic measures of online attention that capture the general public's interest in specific influencers. Through a difference-in-differences approach, we find that deplatforming reduces online attention toward influencers. After 12 months, we estimate that online attention toward deplatformed influencers is reduced by -63% (95% CI [-75%,-46%]) on Google and by -43% (95% CI [-57%,-24%]) on Wikipedia. Further, as we study over a hundred deplatforming events, we can analyze in which cases deplatforming is more or less impactful, revealing nuances about the intervention. Notably, we find that both permanent and temporary deplatforming reduce online attention toward influencers; Overall, this work contributes to the ongoing effort to map the effectiveness of content moderation interventions, driving platform governance away from speculation.

翻译：从政客到播客主持人，在线平台因违反平台准则而系统性地封禁（"deplatforming"）有影响力的用户。此前关于此干预措施有效性的研究尚无定论，原因在于：1）仅考察了少数封禁事件；2）仅考察了显性互动痕迹（如点赞、发帖），而未考虑被动参与（如浏览量）；3）未考虑受封禁事件影响的用户可能迁移的所有潜在平台。我们通过一项针对101名影响者涉及的165次封禁事件的纵向准实验研究，弥补了上述局限。我们从Reddit帖子中收集封禁事件并人工整理数据，确保这一大规模封禁事件数据集准确性。随后，我们将这些事件与谷歌趋势（Google Trends）和维基百科页面浏览量（平台无关的在线关注度指标，可反映公众对特定影响者的兴趣）进行关联。通过双重差分分析法，我们发现封禁降低了公众对影响者的在线关注度。12个月后，我们估计封禁后影响者在谷歌上的在线关注度下降了63%（95%置信区间[-75%, -46%]），在维基百科上下降了43%（95%置信区间[-57%, -24%]）。此外，由于我们研究了百余次封禁事件，可分析不同情境下封禁效果强弱差异，揭示干预措施的细微特征。值得注意的是，我们发现永久封禁与临时封禁均能降低公众对影响者的在线关注度；总体而言，本研究为持续探索内容审核干预效果、推动平台治理脱离臆测提供了实证依据。