Pareto's 80/20 law and social differentiation: A social entropy perspective

•Uneven online contributions reflect social differentiation.•Wikipedia Leadership is adhocractic: it changes, but slow and osmoticaly.•.1% of Wikipedians generate 40% of the content.•Adhocratic social media reach a steady state with a social order and leadership.

Unequal contributions to social media, whereby a vast amount of content is produced by a limited number of users, need a better, theoretically grounded explanation. The present paper argues that contribution inequality on social media can be considered a symptom of social differentiation, which can be detected via social entropy. A conceptual foundation for this perspective is offered, supported by an empirical example. We use social entropy to detect the evolution of contribution inequality on Wikipedia over a period of 9 years. The paper also offers suggestions for using the conceptual framework for better understanding social media contribution structure and functional roles for practical applications.