Broadcast information diffusion processes on social media networks: exogenous events lead to more integrated public discourse.

The article focuses on how information diffusion patterns—specifically broadcast spreading and viral spreading—shape public discourse dynamics on social media, using Twitter data from 2020 and simulation studies. Broadcast spreading, defined as information diffusion influenced by external sources beyond peer-to-peer networks, is associated with increased integration of discourse networks, where collective attention concentrates on specific topics during eventful periods. In contrast, viral spreading, characterized by peer-to-peer diffusion constrained within social network communities, tends to maintain or increase discourse segregation, leading to fragmented and modular public conversations. The study finds that public discourse oscillates between these integrated and segregated states, influenced by real-world events and the type of information diffusion, highlighting the complex and dynamic nature of social media's impact on public dialogue.