Enabling Collaborative Data Sharing in Google+

Most of existing online social networks, such as Facebook and Twitter, are designed to bias towards information disclosure to a large audience. Google recently launched a new social network platform, Google+. By introducing the notion of 'Circles', Google+ enables users to selectively share data with specific groups within their personal network, rather than sharing with all of their social connections at once. Although Google+ can help mitigate the gap between the individuals' expectations and their actual privacy settings, it still only allows a single user to restrict access to their data but cannot provide any mechanism to enforce privacy concerns over data associated with multiple users.