  Diffusion of information and viral content, social contagion and influence
are still topics of broad evaluation. We have studied the information epidemic
in a social networking platform in order compare different campaign setups. The
goal of this work is to present the new knowledge obtained from studying two
artificial (experimental) and one natural (where people act emotionally) viral
spread that took place in a closed virtual world. We propose an approach to
modeling the behavior of online community exposed on external impulses as an
epidemic process. The presented results base on online multilayer system
observation, and show characteristic difference between setups, moreover, some
important aspects of branching processes are presented. We run experiments,
where we introduced viral to system and agents were able to propagate it. There
were two modes of experiment: with or without award. Dynamic of spreading both
of virals were described by epidemiological model and diffusion. Results of
experiments were compared with real propagation process - spontaneous
organization against ACTA. During general-national protest against new
antypiracy multinational agreement - ACTA, criticized for its adverse effect on
e.g. freedom of expression and privacy of communication, members of chosen
community could send a viral such as Stop-ACTA transparent. In this scenario,
we are able to capture behavior of society, when real emotions play a role, and
compare results with artificiality conditioned experiments. Moreover, we could
measure effect of emotions in viral propagation. As theory explaining the role
of emotions in spreading behaviour as an factor of message targeting and
individuals spread emotional-oriented content in a more carefully and more
influential way, the experiments show that probabilities of secondary
infections are four times bigger if emotions play a role.
