Due to the ability of cell phone providers to use cell phone towers to pinpoint usersâ€™ locations, the increasing popularity of GPS capabilities in cell phones, and the rise of cell phones for Internet use, a plethora of new applications have been developed that share users' real-time location information online. Foursquare, Loopt, and Google Latitude are just a few examples. This talk will discuss usersâ€™ risk and benefit perceptions related to the use of these technologies and the privacy controls of existing location-sharing applications. We'll also discuss Locaccino, a location-sharing service we developed to provide a platform for experimenting with privacy controls for end users. Locaccino provides users with precision control over who can see their location. While most location-based systems only allow users to list which contacts should or shouldnâ€™t be able to see their location, Locaccino offers more granular privacy settings.