We focus on privacy in Social Network Sites, but do we really understand what happens in Social Network Sites? Why do people disclose so much identity-relevant information to a website and what trade-offs do users face? Associate professor Ronald Leenes from Tilburg University dives deeper into the concept of Social Network Sites. Q&A after presentation that is part of the conference on Privacy in Social Network Sites, October 23 and 24, 2008, at Delft University of Technology. www.privacyinsocialnetworksites.nl.