While the collection and monetization of user data has become a main source for funding "free" services like search engines, on-line social networks, news sites and blogs, neither privacy-enhancing technologies nor its regulations have kept up with user needs and privacy preferences.

The aim of this Dagstuhl Perspectives Workshop is to raise awareness for the actual state of the art of on-line privacy, especially in the international research community and in ongoing efforts to improve the respective legal frameworks, and to deliver soon after the workshop a Dagstuhl Manifesto providing recommendations to industry, regulators, and research agencies for improving on-line privacy. In particular we have examined how the basic principle of informational self-determination, as promoted by European legal doctrines, could be applied to infrastructures like the Internet, Web 2.0 and mobile telecommunication networks.

It was deemed necessary and timely to bring together a broad spectrum of key contributors in order to promote both legally and commercially viable foundations for a balanced on-line privacy:

• Academia (specifically data security, privacy, cyber-law, and privacy-influential technologies & services),
• Public sector (data protection officers, organizers of relevant research programs, relevant civil rights organizations), and
• Industry (providers of communication solutions, browsers and apps; data aggregation and web analytics companies; providers of major Internet and mobile Internet services)

This workshop and its planned Dagstuhl Manifesto have four goals, aside from galvanizing an emerging research community:

1. Provide a big picture of on-line privacy, which can be understood widely Because of swift progress in the mobile Internet, on-line social networks, and on-line advertisements, it is a challenge for non-experts (and perhaps even experts themselves) to understand the current state of on-line privacy including the technologies and systems to collect personal information on-line.
2. Compile the industry and engineering options to improve on-line privacy. On-line privacy depends on the technologies and systems used to access Internet/Web 2.0 services as well as on the services provided to users. Therefore industry has a strong influence.
3. Update the respective legislative and regulative authorities on their options for enforcing practical, commercially viable informational self-determination of users in global infrastructures (e.g. EU’s Privacy Directive to be revised in 2011). Access to personal information is critical to self-determination; it is also seen as a right that serves a policing function among information-intensive firms. However, legal and business structures have often foreclosed rights of access, or made them impracticable for consumers to exercise.
4. Foster industry’s and academia’s research for creating effective on-line privacy technologies, components, and systems that promote informational self-determination. Corresponding to additional risks for on-line privacy, new approaches are required in research to again establish adequate levels of on-line privacy.

This workshop has been structured into four parts, for each part, a topic responsible has been assigned:

• Part 1. Current S-o-A of on-line privacy w.r.t. to informational self-determination Responsible: Alma Whitten, Google Research
• Part 2. Industry & Engineering Options to improve on-line privacy Responsible: Michael Waidner, ex-IBM CTO Security, then TU Darmstadt, Germany
• Part 3. Recommendations for improving regulations of online privacy Responsible: Caspar Bowden, MS UK
• Part 4. Recommendations for research to improve the S-o-A of online privacy Responsible: Kai Rannenberg, Goethe University, Frankfurt, Germany

A Dagstuhl Manifesto conclude this workshop.