  Social networks can have asymmetric relationships. In the online social
network Twitter, a follower receives tweets from a followed person but the
followed person is not obliged to subscribe to the channel of the follower.
Thus, it is natural to consider the dissemination of information in directed
networks. In this work we use the mean-field approach to derive differential
equations that describe the dissemination of information in a social network
with asymmetric relationships. In particular, our model reflects the impact of
the degree distribution on the information propagation process. We further show
that for an important subclass of our model, the differential equations can be
solved analytically.
