FIG. 1: Revenues of the movies are shown as functions of date. Revenue data is the value in Japanese market. The movie titles are as follows. A:Death Note, B:Death Note the last name, C: zoku Always, D: Close zero, E: Closed Note, F:Biohazard 3, G:Bushi no Ichibun, H:Ratatouille, I:fra-girl, J:Dainihonjin, K:Maiko haaaan!!, L:Koizora, M:HERO. audience at the time t to be N ( t ). Thus, the number of people who have interest on the movie is N$_{0}$ − N ( t ). When we assume that the probability to watch the movie per one day is a , we obtain the equation to describe the number of audience to be The solution of the equation is Thus, when the initial condition is N ( t ) = 0 at t = 0, we obtain It is clear that the result can be explain roughly the exponential decay of the audience shown in fig.1. Next, we compare the daily change of the revenue data with the number of the entry of the blog writing. The typical results are shown in figs.2-5. The data shows the exponential dN ( t ) dt = a ( N$_{0}$ − N ( t )) (1) N ( t ) = N$_{0}$ − Ce − at (2) N ( t ) = N$_{0}$ (1 − e − $^{at}$) (3) 3