Global regularities and regional patterns in social media discourse: Topic variety, language diversity, and user behavior across 29 cities

In our increasingly interconnected world, digital communication operates with variable geographic reach. Distinguishing between regionally and globally discussed issues allows us to better understand the geographical relevance of topics in digital urban discourses. This study compared the diversity of topics, languages, and user behaviors across 29 cities around the world using Twitter (now X) data posted around New Year's Eve 2021–2022. Applying topic modeling, we identified 145 topics and classified them into relative types of geographic diffusion (i.e., ‘low’, ‘intermediate’, or ‘global’) according to the number of cities and world regions where they were discussed. Topics discussed across the globe included “Food”, “Music”, “Family”, “Religion”, and “Politics”, while conversations with a low relative diffusion reflected on region-specific issues such as “Brexit” in the UK or the “Year of the Tiger” in East Asia. Intermediate topics such as “Healthcare/Medicine”, “Feminism”, and “Booster Vaccination” were common across most regions but displayed distinct emphases. Topic diversity tended to increase with language diversity, and the number of languages used increased as topics shifted from low to global diffusion. Twitter user behavior exhibited consistent Zipf-like patterns across all cities, with a small fraction of highly active users producing most tweets and discussing the highest number of topics. Regional differences emerged, with East and South-East Asian cities showing more balanced user participation and European and North American ones being the most unequal. Viewed through the lens of social media, these patterns reveal both the commonalities that connect human societies and the persistent differences that define them, reflecting a world that is increasingly interconnected but far from being homogeneous.