Power-Law Properties of Human View and Reply Behavior in Online Society

Statistical properties of the human comment behavior are studied using data from "Tianya" and "Tieba" which are very popular online social systems (or forums) in China. We find that both the reply number R and the view number V of a thread in a subforum obey the power-law distributions P(R) = R-alpha and P(V) alpha V-beta, respectively, which indicates that there exists a kind of highly popular topics. These topics should be specially paid much attention, because they play an important role in the public opinion formation and the public opinion control. In addition, the relationship between R and V also obeys the power-law function R alpha V-gamma. Based on the human comment habit, a model is introduced to explain the human view and reply behaviors in the forum. Numerical simulations of the model fit well with the empirical results. Our findings are helpful for discovering collective patterns of human behaviors and the evolution of public opinions on the virtual society as well as the real one.