Online users struggle with different concerns whenever they use information systems. According to Miyazaki and Fernandez (2001), there are three important categories of concerns for online users: privacy concern, third party fraudulent behavior concern ("system security"), and online website fraudulent behavior concern ("security"). Kim, Sivasailam, and Rao (2004) proposed a similar categorization for web assurance dimensions. They argue that online websites are supposed to address users' privacy, security, and business integrity concerns to decrease user concerns. Although several researchers tried to answer how different factors affect these concerns and how these concerns affect users' behavior, there are so many ambiguities and contradictions in this area. This Essay I in this work develops a comprehensive map of the role of online privacy concern to identify related factors and categorize them through an in-depth literature review and conducting meta-analysis on online privacy concern. Although users have concerns about their privacy and security, there is still growth in the number of internet users and electronic commerce market share. One possible reason is that websites are applying assurance mechanisms to ensure the privacy of their users. Therefore, it could be an interesting research topic to investigate how privacy assurance mechanisms affect users concern and, consequently, their behavior in different concerns such as e-commerce and social networking sites. Different types of web assurance mechanisms are used by websites. The most prevalent among these assurance mechanisms include web assurance seals and assurance statements and privacy customization features. Essay II and III aims to address how these mechanisms influence e-commerce and social networking sites users' behavior. Essay II applies the procedural fairness theory by Lind and Tyler (1988) to explain how and why the web assurance mechanisms affect consumers' perceived risks. Essay III addresses the issue of self-disclosure on social networking sites. Applying protection motivation theory, this study aims to evaluate the effect of web assurance mechanisms on online privacy concern and self-disclosure behavior on the social networking sites.