Crucial moment. How minor changes lead to global changes

How does fashion arise? Why is it growth and decline in crime? How do books by unknown authors become bestsellers? How does addiction to smoking spread among adolescents? To understand how the phenomenon of the crowd and many other mass phenomena characteristic of today"s life arise, they should be considered as epidemics. Ideas, goods, information and types of behavior spread in the same way as viruses. Small efforts attached in the right place are enough to create a global trend. The author seeks to answer two main questions: why do some ideas, types of behavior or products cause epidemics, while others do not, and what we can do in order to cause beneficial epidemics and consistently manage them