1. A system for efficiently transmitting an electronic message, the system comprising: a weight data store configured to store information regarding interaction strengths between participants in an online social network (OSN); at least one computing device configured to provide an influence calculation engine configured to: receive a feed representing activities between participants on the OSN; analyze the activities using a Helmholtz Green's Function (HGF) matrix (G) to determine overall influence weights that represent likelihoods that participants in the OSN will propagate messages; and store the determined weights in the weight data store; and at least one computing device configured to provide an interface engine configured to: receive a message to be propagated via the OSN; query the weight data store based on the determined weights to select one or more participants to propagate the message; and transmit the message to the selected one or more participants for propagation.