  In recent times there has been a surge of interest in seeking out patterns in
the aggregate behavior of socio-economic systems. One such domain is the
emergence of statistical regularities in the evolution of collective choice
from individual behavior. This is manifested in the sudden emergence of
popularity or "success" of certain ideas or products, compared to their
numerous, often very similar, competitors. In this paper, we present an
empirical study of a wide range of popularity distributions, spanning from
scientific paper citations to movie gross income. Our results show that in the
majority of cases, the distribution follows a log-normal form, suggesting that
multiplicative stochastic processes are the basis for emergence of popular
entities. This suggests the existence of some general principles of complex
organization leading to the emergence of popularity. We discuss the theoretical
principles needed to explain this socio-economic phenomenon, and present a
model for collective behavior that exhibits bimodality, which has been observed
in certain empirical popularity distributions.
