## 2 Materials and Methods  
Privacy, as a multifaceted concept, presupposes different privacy perceptions and management strategies for different users in SNs, which differentiate even more because their diverse socio-contextual backgrounds. Due to this complexity, it is often difficult to be measured, so as to reflect users' social privacy norms and therefore to lead to the proper technical privacy measures development for managing privacy issues within social networks in a self-adaptive way [26]. Despite the fact that users' social landscape is of vital importance for understanding their privacy perceptions and behaviors, most of previous works, regarding users' privacy management [27; 28], fragmentary include social factors in their measurement scales, addressing consequently privacy as a one-layered construct. To meet that need, the measurement instrument that was developed, adopted constructs and their respective metrics from both sociological and privacy literature, aiming at examining multiple information about users' social attributes and privacy management within SNs. As far as the sociological literature concerns, it put special emphasis on social identity theory metrics and social capital theory metrics, since both social identity and social capital concepts have been highlighted by previous research to influence users' privacy management within SNs [29; 30]. Social identity refers to the ways that individuals determine their attitudes and practices in each domain of activity, based on specific social attributes, which represent their personal social categories and characteristics [31]. Furthermore, previous literature supports that there is a high possibility for individuals to gain more resources when they belong to many groups [32], and in this sense, users' social identity affects their social capital. Social capital captures the gains and the advantages that individuals obtain by participating in networks and social institutions [33]. Two types of social capital are referred by previous literature to affect privacy management, the Bonding and the bridging one [34]. Bonding social capital concerns the development of coherent ties among individuals within tight networks, experiencing similar situations and exchanging support and trust, such as family or close friends. Bridging social capital refers to the development of connective ties among individuals within vulnerable, heterogeneous, and diverse networks, experiencing different situations, without a common sense of belonging [33]. Consequently, in contrast to previous research that has examined these social constructs separately, in our work they are both examined, in order to provide further understanding of users' social landscape. Privacy literature was thoroughly investigated in order for the validated metrics of previous works regarding privacy perceptions and management to be adopted in our instrument. Since privacy, apart from the several definitions of its concept; it has specific and very often descriptive and measurable interactive functions within a society [26], such as privacy concerns, privacy risks, and privacy behaviors, it was important to incorporate these measures in our instrument. [PERSON] in [35], for instance, argues about individuals' management strategy to remain anonymous and untraceable within SNs, not only by not providing personal information at all, but also by providing untrue information in order for not to be visible while online [36]. The specific privacy metrics are described in detail as follows. Therefore, the questionnaire that was developed for the data collection, included three wider sections, concerning users' social identity, users' social capital and users' privacy management within social networks, along with their respective items.