document: Structure and evolution of online social networks In this paper , we consider the evolution of structure within large online social networks . We present a series of measurements of two such networks , together comprising in excess of five million people and ten million friendship links , annotated with metadata capturing the time of every event in the life of the network . Our measurements expose a surprising segmentation of these networks into three regions : singletons who do not participate in the network ; isolated communities which overwhelmingly display star structure ; and a giant component anchored by a well-connected core region which persists even in the absence of stars . We present a simple model of network growth which captures these aspects of component structure . The model follows our experimental results , characterizing users as either passive members of the network ; inviters who encourage offline friends and acquaintances to migrate online ; and linkers who fully participate in the social evolution of the network .
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