  We present a study of information flow that takes into account the
observation that an item relevant to one person is more likely to be of
interest to individuals in the same social circle than those outside of it.
This is due to the fact that the similarity of node attributes in social
networks decreases as a function of the graph distance. An epidemic model on a
scale-free network with this property has a finite threshold, implying that the
spread of information is limited. We tested our predictions by measuring the
spread of messages in an organization and also by numerical experiments that
take into consideration the organizational distance among individuals.
