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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 

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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 

