In this short workshop you will learn how to map the cookie ecology related to a set of websites using the DMI Tracker Tracker tool and Gephi. The Tracker Tracker tool was conceived at the Digital Methods Winterschool 2012 in January. It is build on top of the anti-tracking plugin www.ghostery.com and allows to identify the invisible web, devices that track user activities online and the services associated to them. In order to prepare for this workshop we recommend reading the related projects and materials listed below. Please download and install Gephi at https://gephi.org/ before the workshop starts so you can also learn how to visualize your results.