An Analysis of P3P-Enabled Web Sites among Top-20 Search Results


Search engines play an important role in helping users find desired content. With the increasing deployment of computer-readable privacy policies encoded using the standard W3C Platform for Privacy Preferences (P3P) format, search engines also have the potential to help users identify web sites that will respect their privacy needs. We conducted a study of the quantity and quality of P3P-encoded privacy policies associated with top-20 search results from three popular search engines. We built a P3P-enabled search engine and used it to gather statistics on P3P adoption as well as the privacy landscape of the Internet as a whole. This search engine makes use of a privacy policy cache that we designed to facilitate fast searches. Using a list of "typical" search terms taken from AOL users' queries, we examined the trends in privacy policies that are returned from queries to the AOL, Google, and Yahoo! search engines. We then compared these results to results compiled after using "e-commerce search terms" from Google's Froogle service. We examined the top 20 search results returned by each search engine for each of the search terms and found at least one result with a P3P policy for 83% of the typical search terms. Overall we found that these typical search terms yielded P3P adoption rates of 10%. This contrasts with adoption rates of 21% percent when searching for e-commerce terms. Examining the content of the policies, we discovered that overall a minority of sites engage in direct marketing with or without a way of opting out, and that even fewer sites share personal information with other companies. Finally, we outline ways to increase P3P adoption rates as well as decrease policy errors.


Serge Egelman, Lorrie Faith Cranor, and Abdur Chowdhury. An Analysis of P3P-Enabled Web Sites among Top-20 Search Results. Proceedings of the Eighth International Conference on Electronic Commerce August 14-16, 2006, Fredericton, New Brunswick, Canada.

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Lorrie Faith Cranor