Open Challenges in Relationship-Based Privacy Mechanisms for Social Network Services

Social networking services (SNSs) such as Facebook and Twitter have experienced explosive growth during the few past years. Millions of users have created their profiles on these services because they experience great benefits in terms of friendship. SNSs can help people to maintain their friendships, organize their social lives, start new friendships, and meet others who share their hobbies and interests. However, all these benefits can be eclipsed by the privacy hazards that affect people in SNSs. People expose intimate information about their lives on SNSs, and this information affects the way others think about them. It is crucial that users be able to control how their information is distributed through the SNSs and decide who can access it. This article presents a list of privacy threats that can affect SNS users and what requirements privacy mechanisms should fulfill to prevent this threats. Then the article reviews current approaches and analyzes to what extent they cover the requirements.     

BFF: A tool for eliciting tie strength and user communities in social networking services

The use of social networking services (SNSs) such as Facebook has explosively grown in the last few years. Users see these SNSs as useful tools to find friends and interact with them. Moreover, SNSs allow their users to share photos, videos, and express their thoughts and feelings. However, users are usually concerned about their privacy when using SNSs. This is because the public image of a subject can be affected by photos or comments posted on a social network. In this way, recent studies demonstrate that users are demanding better mechanisms to protect their privacy. An appropriate approximation to solve this could be a privacy assistant software agent that automatically suggests a privacy policy for any item to be shared on a SNS. The first step for developing such an agent is to be able to elicit meaningful information that can lead to accurate privacy policy predictions. In particular, the information needed is user communities and the strength of users’ relationships, which, as suggested by recent empirical evidence, are the most important factors that drive disclosure in SNSs. Given the number of friends that users can have and the number of communities they may be involved on, it is infeasible that users are able to provide this information without the whole eliciting process becoming confusing and time consuming. In this work, we present a tool called Best Friend Forever (BFF) that automatically classifies the friends of a user in communities and assigns a value to the strength of the relationship ties to each one. We also present an experimental evaluation involving 38 subjects that showed that BFF can significantly alleviate the burden of eliciting communities and relationship strength.     

Factors affecting privacy disclosure on social network sites: an integrated model

The self-disclosure of personal information by users on social network sites (SNSs) play a vital role in the self-sustainability of online social networking service provider platforms. However, people’s levels of privacy concern increases as a direct result of unauthorized procurement and exploitation of personal information from the use of social networks which in turn discourages users from disclosing their information or encourages users to submit fake information online. After a review of the Theory of Planned Behavior (TPB) and the privacy calculus model, an integrated model is proposed to explain privacy disclosure behaviors on social network sites. Thus, the aim of this paper is to find the key factors affecting users’ self-disclosure of personal information. Using privacy calculus, the perceived benefit was combined into the Theory of Planned Behavior, and after some modifications, an integrated model was prescribed specifically for the context of social network sites. The constructs of information sensitivity and perceived benefit were redefined after reviewing the literature. Through a study on the constructs of privacy concern and self-disclosure, this article aims at reducing the levels of privacy concern, while sustaining online transactions and further stimulating the development of social network sites.     

The Taste for Privacy: An Analysis of College Student Privacy Settings in an Online Social Network

The rapid growth of contemporary social network sites (SNSs) has coincided with an increasing concern over personal privacy. College students and adolescents routinely provide personal information on profiles that can be viewed by large numbers of unknown people and potentially used in harmful ways. SNSs like Facebook and MySpace allow users to control the privacy level of their profile, thus limiting access to this information. In this paper, we take the preference for privacy itself as our unit of analysis, and analyze the factors that are predictive of a student having a private versus public profile. Drawing upon a new social network dataset based on Facebook, we argue that privacy behavior is an upshot of both social influences and personal incentives. Students are more likely to have a private profile if their friends and roommates have them; women are more likely to have private profiles than are men; and having a private profile is associated with a higher level of online activity. Finally, students who have private versus public profiles are characterized by a unique set of cultural preferences—of which the “taste for privacy” may be only a small but integral part.     

Teens’ concern for privacy when using social networking sites: An analysis of socialization agents and relationships with privacy-protecting behaviors

U.S. teens are spending substantial time on social networking sites (SNSs). Yet, only a few studies have documented teens’ privacy-protecting behaviors on SNSs. Using data of Facebook teen users and their parents in the U.S. from the Pew Internet’s Teens & Privacy Management Survey (N = 622), this study investigated the socialization agents of teens’ level of online privacy concern, and the relationship between teens’ level of online privacy concern and their privacy-protecting behaviors on SNSs. Based on path analysis results, this study identified parents and SNS use as the two significant socialization agents. In particular, this study revealed the role of parents’ privacy concern and the role of SNS use in motivating teens to increase online privacy concern, which, in turn, drives teens to adopt various privacy-setting strategies on SNSs and to set their Facebook profiles to private. Implications for policymakers and educators were discussed.     

Control your Facebook: An analysis of online privacy literacy

For an effective and responsible communication on social network sites (SNSs) users must decide between withholding and disclosing personal information. For this so-called privacy regulation, users need to have the respective skills—in other words, they need to have online privacy literacy. In this study, we discuss factors that potentially contribute to and result from online privacy literacy. In an online questionnaire with 630 Facebook users, we found that people who spend more time on Facebook and who have changed their privacy settings more frequently reported to have more online privacy literacy. People with more online privacy literacy, in turn, felt more secure on Facebook and implemented more social privacy settings. A mediation analysis showed that time spend on Facebook and experience with privacy regulation did not per se increase safety and privacy behavior directly, stressing the importance of online privacy literacy as a mediator to a safe and privacy-enhancing online behavior. We conclude that Internet experience leads to more online privacy literacy, which fosters a more cautious privacy behavior on SNSs.     

An Extended Privacy Calculus Model for SNSs: Analyzing Self‐Disclosure and Self‐Withdrawal in a Representative U.S. Sample

The privacy calculus established that online self‐disclosures are based on a cost‐benefit tradeoff. For the context of SNSs, however, the privacy calculus still needs further support as most studies consist of small student samples and analyze self‐disclosure only, excluding self‐withdrawal (e.g., the deletion of posts), which is essential in SNS contexts. Thus, this study used a U.S. representative sample to test the privacy calculus' generalizability and extend its theoretical framework by including both self‐withdrawal behaviors and privacy self‐efficacy. Results confirmed the extended privacy calculus model. Moreover, both privacy concerns and privacy self‐efficacy positively predicted use of self‐withdrawal. With regard to predicting self‐disclosure in SNSs, benefits outweighed privacy concerns; regarding self‐withdrawal, privacy concerns outweighed both privacy self‐efficacy and benefits.     

The bittersweet escape to information technology: An investigation of the stress paradox of social network sites

It seems counterintuitive for people to continue using Social network sites (SNSs) despite the stress they cause. This study addresses this issue by suggesting that a stress paradox exists on SNSs, and by developing process and variance theoretical models to explain this new type of IT-duality. It argues that SNS use occurs as a coping strategy that people adopt to deal with life-stress. It also argues that SNSs are stressful, due to more than excessive demands, since SNS use also involves privacy threats. An online survey of 633 Facebook, Instagram and Snapchat users provide support for the study’s main premise.     

Revealing the relationship between rational fatalism and the online privacy paradox

Previous research has revealed the privacy paradox, which suggests that despite concern about their online privacy, people still reveal a large amount of personal information and don’t take measures to protect personal privacy online. Using data from a national-wide survey, this study takes a psychological approach and uses the rational fatalism theory to explain the privacy paradox on the Internet and the social networking sites (SNSs). The rational fatalism theory argues that risks will become rational if the person believes he or she has no control over the outcome. Our results support the rational fatalism view. We found that people with higher levels of fatalistic belief about technologies and business are less likely to protect their privacy on the Internet in general, and the SNS in particular. Moreover, such relationship is stronger among young Internet users compared with older users.     

Blogging privacy rule orientations,privacy management,and content deletion practices: The variability of online privacy management activity at different stages of social media use

The purpose of this study was to examine social media users’ blogging privacy rule orientations, privacy management regulation, and content deletion practices as distinct types of activity occurring at different stages of the blogging process (before, during, and after blogging) that may aid in understanding the functioning of blogging disclosure activity overall. The study was guided by a complementary application of both the uses and gratifications perspective and communication privacy management (CPM) theory. A central tenet of both theories suggests that people are variably active in their communication behavior. We identified five discrete blogger privacy rule orientations explaining different online choice-making practices: the self-centric, the utilitarian, the planner, the protector, and the unworried orientations toward blogging. We also identified six different motives for deleting previously-posted information: conflict management, protection of personal identity/safety, fear of retribution, employment security, impression management, emotional regulation, and relational cleansing. Path analysis revealed several direct and indirect paths among bloggers’ motives for deleting previously posted material and their level of disinhibition, blogging privacy rule orientations, amount of time blogging, and privacy management practices. As use of social media increases, exploring variations in privacy management regulation practices is critical.     

Managing privacy boundaries together: Exploring individual and group privacy management strategies in Facebook

Most research on privacy management within the context of social network sites (SNSs) treats users as individual owners of private information. Privacy, however, is beyond individual control and is also managed on a group level. This study applies the Communication Privacy Management theory (CPM) to explore the individual and group privacy management strategies in Facebook. We present a survey completed by 900 members of a youth organization regarding their online behaviors and membership. We found that women are more likely to employ individual privacy management strategies, while men are more likely to employ group privacy management strategies. For group privacy management, we found common bond and the role an individual is attributed within the youth organization to be the strongest predictors. The results generated from this study are a first but important step to illustrate the differences and similarities between individual and group privacy management. We argue that it is necessary to further study and understand group privacy to better approach users’ privacy needs.     

Die Rolle der Kultur in der Selbstoffenbarung und Privatsph?re in sozialen Onlinenetzwerken

Social Network Sites (SNSs) rely exclusively on user-generated content to offer engaging and rewarding experience to its members. As a result, stimulating user communication and self-disclosure is vital for the sustainability of SNSs. However, considering that the SNS users are increasingly culturally diverse, motivating this audience to self-disclose requires understanding of their cultural intricacies. Yet existing research offers only limited insights into the role of culture behind the motivation of SNS users to self-disclose. Building on the privacy calculus framework, this study explores the role of two cultural dimensions ?C individualism and uncertainty avoidance ?C in self-disclosure decisions of SNS users. Survey responses of US and German Facebook members are used as the basis for our analysis. Structural equation modeling and multi-group analysis results reveal the distinct role of culture in the cognitive patterns of SNS users. The authors find that trusting beliefs play a key role in the self-disclosure decisions of users from individualistic cultures. At the same time, uncertainty avoidance determines the impact of privacy concerns. This paper contributes to the theory by rejecting the universal nature of privacy calculus processes. The findings provide for an array of managerial implications for SNS providers as they strive to encourage content creation and sharing by their heterogeneous members.     

Use of social network sites among depressed adolescents

Social network sites (SNSs) are relatively new phenomena, and the relationship between SNSs and psychopathology remains unclear. The purpose of this study was to evaluate the type of SNSs depressed adolescents use and the incidence of depressive disclosure on SNSs among them. The study was designed to be cross-sectional. The sample consisted of 53 adolescents diagnosed with depressive disorder, as confirmed by K-SADS-PL, and 55 non-depressed adolescents. The Children’s Depression Inventory, Social Anxiety Scale and Social Network Use Questionnaire were administered. The primary finding was that the amount of time spent on the Internet and on SNSs was significantly higher among depressed adolescents than non-depressed adolescents. Additionally, depressed adolescents reported significantly higher disclosure of anhedonia, worthlessness, guilt, loss of concentration, irritability and thoughts of suicide on SNSs. The intensity of the depression sharing was significantly higher in the depressed group. Depressed young people use social networks to express their symptoms. Adolescents’ disclosure on social networks may be able to guide relatives, friends and mental health professionals.     

Predicting selfie-posting behavior on social networking sites: An extension of theory of planned behavior

Over the past few years, a notable trend has emerged in social networking sites (SNSs). With the growing popularity of image-based SNSs such as Instagram, users increasingly communicate and present themselves by posting photographs they take of themselves (“selfies”). As the phenomenon of selfies becomes widespread across a range of SNSs as a unique means of self-presentation, an interesting question arises, what makes people post their selfies on SNSs. To delve into this rising issue, the present study investigates the antecedents of selfie-posting behavior on SNSs by applying and extending Ajzen's Theory of Planned Behavior (TPB). A conceptual model, which is primarily drawn from the TPB and incorporates narcissism as an additional antecedent, is proposed and empirically tested. Results show that attitude toward selfie-posting, subjective norm, perceived behavioral control, and narcissism are the significant determinants of an individual's intention to post selfies on SNSs. Further, one's selfie-posting behavior on SNSs is significantly predicted by his or her intention to post selfies. Implications of the findings are discussed with suggestions for future research.     

Delineating the dimensions of social support on social networking sites and their effects: A comparative model

Social networking sites (SNSs) allow users to connect with each other by overcoming geographical and temporal boundaries and thus empower people to search for social support from online. Social support has been considered a key social value that online users can obtain from SNSs. However, few studies have systematically investigated social support in such a context. Motivated to address this gap, we have developed an advanced and theoretical framework to delineate social support on SNSs by clearly revealing the dimensions of online social support on SNSs and examining their effects on users' commitment and SNS continuance. Further, we introduce gender as a key moderator and explain in theory how differently men and women perceive the importance of the dimensions in evaluating online social support over SNSs. Our research results indicate that the identified three dimensions (informational support, emotional support, and network management) are important components of the online social support on SNSs, which is positively associated with commitment and continuance. In addition, the weight of each dimension in the evaluation of online social support varies by gender. This study is among the very first to explore online social support in the context of SNS and its effects, and has rich theoretical and practical implications.     

Understanding the intentions of users to ‘stick’ to social networking sites: a case study in Taiwan

Social networking sites (SNSs) are the most popular social platforms for developing personal networks. They provide multiple interactive functions for users to create and use large social networks. To determine why people exhibit ‘stickiness’ to SNSs, this study uses the uses and gratifications theory as an underlying structure and builds the research model with factors of motivational needs and interactivity. Our results showed that social needs, information needs, human–message interaction, and human–human interaction are crucial factors that affect the ‘stickiness’ of users to SNSs. The implications of these findings are presented in this paper.     

Differentially private nonlinear observer design using contraction analysis

Real‐time information processing applications such as those enabling a more intelligent infrastructure are increasingly focused on analyzing privacy‐sensitive data obtained from individuals. To produce accurate statistics about the habits of a population of users of a system, this data might need to be processed through model‐based estimators. Moreover, models of population dynamics, originating for example from epidemiology or the social sciences, are often necessarily nonlinear. Motivated by these trends, this paper presents an approach to design nonlinear privacy‐preserving model‐based observers, relying on additive input or output noise to give differential privacy guarantees to the individuals providing the input data. For the case of output perturbation, contraction analysis allows us to design convergent observers as well as set the level of privacy‐preserving noise appropriately. Two examples illustrate the proposed approach: estimating the edge formation probabilities in a social network using a dynamic stochastic block model, and syndromic surveillance relying on an epidemiological model.     

Community building among deaf and hard of hearing people by using written language on social networking sites

Since D/deaf and hard-of-hearing users of social networking sites (SNSs) may have communication specificities in comparison to hearing people, we proposed a model for understanding what factors affect building online communities. The model includes written language skills, the frequency of written communication, online Deaf and hearing identity, and the tendency for community building. One-hundred-and-sixty-two German D/deaf and hard-of-hearing users completed an online questionnaire in German sign and written language. Evaluation of the model with structural equation modelling revealed three main findings. Firstly, identification with the hearing online world has a positive effect on written language skills, the frequency of written communication on SNSs and indirectly on the tendency to build online communities. Secondly, the frequency of written communication has a positive effect on the tendency to build community. Thirdly, a positive effect of online Deaf identity on the frequency of written communication was found. Our findings may aid in understanding that, despite possible technological constraints, both D/deaf and hard-of-hearing people communicate on SNSs in written language more frequently due to their identification either with the Deaf or hearing online world which results in an increased tendency to build online communities.     

The Future of Social Networks on the Internet: The Need for Semantics

Everyone on the Internet knows the buzzword social networking. Social networking services (SNS) usually offer the same basic functionalities: network of friends listings, person surfing, private messaging etc. With such features, SNSs demonstrate how the Internet continues to better connect people for various social and professional purposes. The fundamental problems with today's SNSs block their potential to access the full range of available content and networked people online. A possible solution is to build semantic social networking into the fabric of the next-generation Internet itself-interconnecting both content and people in meaningful ways. The semantic Web is a useful platform for linking and for performing operations on diverse person-and object-related data gathered from heterogeneous social networking sites. In the other direction, object-centered networks can serve as rich data sources for semantic Web applications.     

Anonymizing popularity in online social networks with full utility

With the rapid growth of social network applications, more and more people are participating in social networks. Privacy protection in online social networks becomes an important issue. The illegal disclosure or improper use of users’ private information will lead to unaccepted or unexpected consequences in people’s lives. In this paper, we concern on authentic popularity disclosure in online social networks. To protect users’ privacy, the social networks need to be anonymized. However, existing anonymization algorithms on social networks may lead to nontrivial utility loss. The reason is that the anonymization process has changed the social network’s structure. The social network’s utility, such as retrieving data files, reading data files, and sharing data files among different users, has decreased. Therefore, it is a challenge to develop an effective anonymization algorithm to protect the privacy of user’s authentic popularity in online social networks without decreasing their utility. In this paper, we first design a hierarchical authorization and capability delegation (HACD) model. Based on this model, we propose a novel utility-based popularity anonymization (UPA) scheme, which integrates proxy re-encryption with keyword search techniques, to tackle this issue. We demonstrate that the proposed scheme can not only protect the users’ authentic popularity privacy, but also keep the full utility of the social network. Extensive experiments on large real-world online social networks confirm the efficacy and efficiency of our scheme.