Information and Communication Theory Group, Department of Mediamatics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands. t.a.knijnenburg@tudelft.nl|Information and Communication Theory Group, Department of Mediamatics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands. t.a.knijnenburg@tudelft.nl|Information and Communication Theory Group, Department of Mediamatics, Faculty of Electrical Engineering, Mathematics and Computer Science, Delft University of Technology, Mekelweg 4, 2628 CD Delft, The Netherlands. t.a.knijnenburg@tudelft.nl