By Dirk HelbingShould we still care about privacy, even though many people don't mind giving a lot of personal data away?
I believe, we do need to care
The feeling of being exposed scares many people, particularly minorities. The success of our society depends a lot on minorities, but these are vulnerable (be it critical intellectuals or artists, billionaires or politicians, teachers or judges, religious or other minorities, which one needs to protect). As the "Volkszählungsurteil" correctly concludes, the continuous and uncontrolled recording of data about individual behaviors is undermining chances of personal, but also societal development. Society needs innovation to adjust to change (such as demographic, environmental, technological or climate change). And innovation needs a cultural setting that allows people to experiment and make mistakes. In fact, many fundamental inventions have been made by accident (Porcelain, for example, resulted from attempts to produce gold). Experimenting is also needed to become an adult who is able to judge situations and take responsible decisions.
Therefore, society needs to be run in a way that is tolerant to mistakes. But today one may get a speeding ticket for having been 1km/h too fast. In future, in our over-regulated world, one might get tickets for almost anything. Big Data would make it possible to discover and sanction any small mistake. In the USA, there are already 10 times more people in prison than in Europe (and more than in China and Russia, too). Is this our future, and does it have anything to do with the free society we used to live in? However, if we would punish only a sample of people making mistakes, how would this be compatible with fairness? Wouldn't this end in arbitrariness and undermine justice? And wouldn't the principle of assumed innocence be gone, which is based on the idea that the majority of us are good citizens, and only a few are malicious and to be found guilty?
Furthermore, undermining privacy questions trust in citizens. This, in turn, undermines the citizens' trust in their government, which is the basis of its legitimacy and power. The saying that "trust is good, but control is better" is not entirely correct: control cannot fully replace trust. A well-functioning and efficient society needs a suitable combination of both.
"Public" without "private" wouldn't work well. Privacy provides opportunities to explore new ideas and solutions. It helps to recover from the stress of daily adaptation and reduces conflict in a dense population of people with diverse preferences and cultural backgrounds.
Public and private are two sides of the same medal. If everything is public, this will eventually undermine social norms. On the long run, the consequence could be a shameless society, or if any deviation from established norms is sanctioned, a totalitarian society.
Therefore, while the effects of mass surveillance and privacy intrusion are not immediately visible, they might still cause a long-term damage by undermining the fabric of our society: social norms and culture. It is highly questionable whether the economic benefits would really outweigh this, and whether a control-based digital society would work at all. I rather expect such societal experiments to end in disaster.
 Silicon Valley is a good example for this culture. Moreover, a global map of innovation clearly shows that fundamental innovation mainly happens in free and democratic societies, see A. Mazloumian et al. Global multi-level analysis of the 'scientific food web', Scientific Reports 3: 1167 (2013), http://www.nature.com/srep/
2013/130130/srep01167/full/ srep01167.html? message-global=remove
 J. Schmieder (2013) Mit einem Bein im Knast - Mein Versuch, ein Jahr lang gesetzestreu zu leben (Bertelsmann).
 Detlef Fetchenhauer, Six reasons why you should be more trustful, TEDx Groningen, https://www.youtube.com/watch? A. Diekmann, W. Przepiorka, and H. Rauhut, Lifting the veil of ignorance: An experiment on the contagiousness of norm violations, preprint http://cess.nuff.ox.ac.uk/