Abstract
This paper considers privacy invasion, such as Street View, resulting from map services on the Internet. Reciprocal privacy invasion can develop into a Prisoners’ Dilemma. A portal site remedies such a dilemma by supplying personal information. However, under excessive supply, the problem worsens with negative utility. Whether such a situation develops or not is dependent on the cost of using a service and the coverage of information. We consider two types of taxation, on personal information and advertisements, in order to bring about a social optimum. Furthermore, we obtain a condition in which taxation brings about large tax revenues to be redistributed to privacy-encroached agents.