6. Conclusions
In this paper, we have shown that studying complex networks from a topological perspective, though the insight offered by network motifs, is a new fundamental approach in understanding the emergence of social networks. Indeed, motifs highlight functional aspects of the driving forces behind online social network creation, ties formation, community emergence, and overall communication trends. Our comprehensive social networks analysis, based on graph metric and fidelity assessments, has found a predisposition for characteristics of regular networks (geo-proximity drives tie formation), followed closely by random network aspects (long range link formation), then, with diminishing predisposition, by small-world properties (tendency to cluster and close triads), and, with very low occurrence, characteristics of scale-free networks (hub formation). Finally, we have shown that each online social platform has quite distinct properties, which imply distinct motif fingerprints, and thus different communication mechanisms.