Privacy Statement

The Privad system is designed from the ground up to be non-tracking and to protect privacy. All messages between user computers and Privad servers pass through an anonymizing third-party proxy, and are encrypted. The proxy cannot see the contents of messages, and therefore cannot learn anything about users. Privad servers never learn the IP addresses of users.

Our privacy policy is simple and unique:

  • Privad does not track users.
  • Privad gathers no Personally Identifying Information (PII), for instance names, street addresses, phone numbers, or credit card numbers.
  • Privad gathers nothing that identifies a user or a user's computer. This includes cookies and Internet addresses.
  • Privad gathers no sensitive information, including health, finances, ethnicity, race, sexual orientation, personal relationships and political activity.

Privad gathers and stores the following information:

  • Anonymous requests for ads containing a keyword combination (a search query or a product title) that identifies a shopping interest.
  • Anonymous ad view and click reports containing the ad id and the web-site host name where the ad was shown.
  • Anonymous error reports to help in software debugging.
  • Differentially private results of queries over ads-related statistical informaion.

The basic purpose of the first two items is to deliver targeted ads to users and to report on their performance (click-through and conversion rates). The last item enables the system to execute numerical queries over ads-related statistics collected at clients (e.g., number of pages visited after an ad click, the amount of time spent browsing an ad landing page, number of bookmarked ads websites). The results of these queries are collected in a differentially private manner, which means that noise is added in such a way that it is impossible to infer presence or absence of a user's contribution in the aggregate query result. This differentially private mechanism allows Privad system to obtain meaningful analytical information without infringing on users privacy.

Please contact privad-privacy@mpi-sws.org if you have any questions, comments, or concerns.