Fluctuation scaling in online social media

To examine number fluctuations in online social media, we focus on the daily appearances of adjectives, abdominal particles, and conjunctions in a Japanese blog space. We show that a non-trivial fluctuation scaling law exists between the standard deviation and the mean. When the number of appearances becomes larger, the standard deviation linearly increases. We introduce a random posting (RP) model, which is inspired by the random diffusion model, to reproduce the observed scaling law. We confirm that the RP model can estimate number fluctuations in a Japanese blog space from both analytical and simulated results.