Figure 1

Sample direct influence network (DIN) for subject S with polarity P. This sample DIN is associated with an observer A (purple node) at the beginning of day 5. On day 4, there was an impression event (node \(e_1\)) in which that observer was served a post \(P_1\) by account B. Thus, observer A may have been influenced by post \(P_1\). Three events are reported on day 3 and raise interesting questions. Should account B (that posted post \(P_1\) on day 3, see event \(e_2\)) receive credit for influencing A?.