  The emergence of research focused to understand the spreading and impact of
disinformation is increasing year over year. Most times, the purpose of those
who start the spreading of information intentionally false and designed to
cause harm is in catalyzing its fast transformation into misinformation, which
is the false content shared by people who do not realize it is false or
misleading. Our interest is in discussing the role of people who decide to
adopt an active role in stopping the propagation of an information when they
realize that it is false. For this, we formulate two simple probabilistic
models to compare misinformation spreading in the possible scenarios for which
there is a passive or an active environment of aware individuals. With aware
individuals we mean those individuals who realize that a given information is
false or misleading. In the passive environment we assume that if one of an
aware individual is exposed to the misinformation then he/she will not spread
it. In the active environment we assume that if one of an aware individual is
exposed to the misinformation then he/she will not spread it but also he/she
will stop the propagation to other individuals from the individual who
contacted him/her. We appeal to the theory of branching processes to analyse
propagation in both scenarios and we discuss the role and the impact of
effective participation in stopping misinformation. We show that the
propagation reduces drastically provided we assume an active environment, and
we obtain theoretical and computational results to measure such a reduction,
which in turns depends on the proportion of aware individuals and the number of
potential contacts of each individual which is assumed to be random.
