Y Social: an LLM-powered Social Media Digital Twin

Online social media (OSM henceforth) have revolutionized the way we exchange information. From the user's perspective, these digital ecosystems are largely effortless [136], enabling convenient ways of exchanging personal content [1], seeking information [129] and synchronizing with others [37]. This convenience has catalyzed a massive digital shift in social and information exchanges from offline to online settings [136], which has provided novel access to massive amounts of online data regarding human behaviour [141]. Unconstrained by geographical barriers, the massive adoption of social media has given rise to novel phenomena that are absent in in-person interactions, such as the influence of complexity and artificial intelligence. Complexity in social media is strongly related to the motto "more is different" [7]: the idea that the co-occurrence of many, even similar, interactions within the same context can lead to unexpected phenomena. Examples include acts as simple and seemingly insignificant as following another user, or re-sharing content. Taken individually, these actions can be understood in terms of a user's activity, psychology, and engagement [91, 97, 141], but when repeated by vast amounts of users, these actions can determine the unexpected rise