  The landscape of information has experienced significant transformations with
the rapid expansion of the internet and the emergence of online social
networks. Initially, there was optimism that these platforms would encourage a
culture of active participation and diverse communication. However, recent
events have brought to light the negative effects of social media platforms,
leading to the creation of echo chambers, where users are exposed only to
content that aligns with their existing beliefs. Furthermore, malicious
individuals exploit these platforms to deceive people and undermine democratic
processes. To gain a deeper understanding of these phenomena, this chapter
introduces a computational method designed to identify coordinated inauthentic
behavior within Facebook groups. The method focuses on analyzing posts, URLs,
and images, revealing that certain Facebook groups engage in orchestrated
campaigns. These groups simultaneously share identical content, which may
expose users to repeated encounters with false or misleading narratives,
effectively forming "disinformation echo chambers." This chapter concludes by
discussing the theoretical and empirical implications of these findings.
