Users online tend to consume information adhering to their system of beliefs and to ignore dissenting information. During the COVID-19 pandemic, users get exposed to a massive amount of information about a new topic having a high level of uncertainty. In this paper, we analyze two social media that enforced opposite moderation methods, Twitter and Gab, to assess the interplay between news consumption and content regulation concerning COVID-19. We compare the two platforms on about three million pieces of content analyzing user interaction with respect to news articles. We first describe users' consumption patterns on the two platforms focusing on the political leaning of news outlets. Finally, we characterize the echo chamber effect by modeling the dynamics of users' interaction networks. Our results show that the presence of moderation pursued by Twitter produces a significant reduction of questionable content, with a consequent affiliation towards reliable sources in terms of engagement and comments. Conversely, the lack of clear regulation on Gab results in the tendency of the user to engage with both types of content, showing a slight preference for the questionable ones which may account for a dissing/endorsement behavior. Twitter users show segregation towards reliable content with a uniform narrative. Gab, instead, offers a more heterogeneous structure where users, independently of their leaning, follow people who are slightly polarized towards questionable news.

中文翻译：

---

新闻消费和社交媒体监管政策

在线用户倾向于消费符合他们信仰体系的信息，而忽略不同意见的信息。在 COVID-19 大流行期间，用户会接触到大量关于具有高度不确定性的新主题的信息。在本文中，我们分析了两种采用相反审核方法的社交媒体 Twitter 和 Gab，以评估有关 COVID-19 的新闻消费和内容监管之间的相互作用。我们在大约 300 万条分析用户与新闻文章交互的内容上比较了这两个平台。我们首先描述用户在两个平台上的消费模式，重点关注新闻媒体的政治倾向。最后，我们通过对用户交互网络的动态进行建模来表征回声室效应。我们的结果表明，Twitter 所追求的节制的存在显着减少了有问题的内容，从而在参与度和评论方面与可靠的来源建立了联系。相反，对 Gab 缺乏明确的监管导致用户倾向于参与两种类型的内容，表现出对有问题的内容的轻微偏好，这可能会导致贬低/认可行为。Twitter 用户表现出对具有统一叙述的可靠内容的隔离。相反，Gab 提供了一个更加多样化的结构，用户可以独立于他们的倾向，关注那些对可疑新闻略有两极分化的人。相反，对 Gab 缺乏明确的监管导致用户倾向于参与两种类型的内容，表现出对有问题的内容的轻微偏好，这可能会导致贬低/认可行为。Twitter 用户表现出对具有统一叙述的可靠内容的隔离。相反，Gab 提供了一个更加多样化的结构，用户可以独立于他们的倾向，关注那些对可疑新闻略有两极分化的人。相反，对 Gab 缺乏明确的监管导致用户倾向于参与两种类型的内容，表现出对有问题的内容的轻微偏好，这可能会导致贬低/认可行为。Twitter 用户表现出对具有统一叙述的可靠内容的隔离。相反，Gab 提供了一个更加多样化的结构，用户可以独立于他们的倾向，关注那些对可疑新闻略有两极分化的人。