  In this paper, we consider how to maximize users' influence in Online Social
Networks (OSNs) by exploiting social relationships only. Our first contribution
is to extend to OSNs the model of Kempe et al. [1] on the propagation of
information in a social network and to show that a greedy algorithm is a good
approximation of the optimal algorithm that is NP-hard. However, the greedy
algorithm requires global knowledge, which is hardly practical. Our second
contribution is to show on simulations on the full Twitter social graph that
simple and practical strategies perform close to the greedy algorithm.
