Passive data is the data that is gathered in the background without any need to interact with a user. In this chapter, the authors explore the process of identifying different data sources and data formats. Although sessions are commonplace in web application development, cookies have not been replaced. The reliability of cookies can be questioned, however, as users who are focused on privacy will often prevent an application from leaving cookies in their web browser. After the JSON has been read in from the cookie it is converted to JavaScript objects. Information about the geographic location associated with the IP address is returned in a JSON structured document. Simplistic data sources in the form of cookies and sessions were explored that contain short term data left by the user and application. The time spent on areas of interest in an application was then described.