Social networks are social systems composed of individuals who interact each other directly or indirectly. An individual has various kinds of relationships in social life and she/he participates in different types of social network structures depending on these relationships. Each social interaction which is a component of the social life has its own internal dynamics and structures with different characteristics. It is necessary to know the characteristics of social networks in order to analyze the structural features of the relationships in the network. In this study, the variabilities in social network structures is examined by local centrality measures that are related to the immediate environment of the individual and by nonlocal centrality measures which define the individual's position in the network, depending on his/her general position among individuals with whom he/she has relationships. In this study, the measures of centralization of the actors in different types of networks, such as friendship network, politic discussion network and Facebook network, each of which is formed by the same members, are examined. Moreover, the specific features of networks have been determined to vary according to network types. Additionally, the claim which states that "Each network differs from other types of networks in terms of their characteristics" is supported by empirical evidence. In summary, individuals on a social network acts independently from their position on other networks, and therefore each type of network should be evaluated within its own internal dynamics.