Understanding social effects in online networks

Understanding the motives behind people´s interactions online can offer sound bases to predict how a social network may evolve and also support a host of applications. We hypothesize that three offline social factors, namely, stature, relationship strength, and egocentricity may also play an important role in driving users´ interactions online. Therefore, we study the influence of these three social factors in online interactions by analyzing the transitivity in triads or three-way relationships among users. Analyzing transitivity through the lens of triad census for four popular social networks, namely, Facebook, Twitter, YouTube and Slashdot, we find that: (i) users´ interactions are largely influenced by intermediary relations, which enhances the mediators´ stature; (ii) the strength of offline relationships plays a salient role in transitivity of relations online; and (iii) egocentricity, embodied in over-active and popular users, has a significant effect on the dynamics of online interactions.