How Private is Your Online Search History?

The queries we enter into online search engines can reveal a great deal of deeply private information about us. A search for "psychologists in Pittsburgh" is pretty revealing; a search for "birth control morning after pill" or "gonorrhea treatment" even more so. Knowing that a person searched for "atheist organizations in Alabama" or "how do I come out of the closet" could expose them to stigma. And entering "divorce lawyer," "domestic violence shelter," or "marriage counseling" can expose sensitive facts, as can searching for "whistleblower protections" or "civil disobedience tactics." Because this information is so revealing, most of us would want it to be protected against snooping and disclosure.

Unfortunately, the public knows little about the policies and practices of the government when it seeks people's search queries from search engine operators as part of a criminal investigation. This information is important, because the major online search engines--Google, Microsoft's Bing, Yahoo!, and Ask.com--log and retain information about users' search queries. The retained information includes not only the search terms entered into the search engines, but also unique identifying information about the users entering those terms, such as the Internet Protocol (IP) address assigned to the user by the user's internet service provider, and the unique cookie ID assigned to the user's computer by the search engine operator itself. Although some search engines automatically encrypt the connection between users' computers and their servers to protect the privacy of search terms as they travel over the internet, search query information is still saved by the companies on their end, and therefore available to law enforcement. (At least one search engine, Duck Duck Go, states that it doesn't log or retain search queries at all).

There are two kinds of information law enforcement might seek from a search engine: records of search queries entered by a particular person or persons; and a list of the names, IP addresses, or other identifying information for some or all people who have entered a particular query into the search engine's webpage. Representatives of the two largest search engines, Google and Bing, have suggested that they think the government needs a warrant to get this information. But we don't know what the government's policies are, nor how the search engines have reacted when presented with a government request for users' search query data. Other than a 2006 instance in which Google resisted an extremely broad Justice Department subpoena for search records, we don't know of any cases where search engines have challenged government requests, in court or out.

It is increasingly difficult to participate fully in today's social, professional, and civic life without accessing the vast trove of information and resources the internet contains. And precisely because the internet is so immense, we must rely on search engines to guide us to its useful and relevant parts. While even a single search query can reveal private information about the person who enters it, a person's whole search history can furnish a detailed profile of her medical diagnoses, religious beliefs, financial stability, sexual desires, relationship status, family secrets, political leanings, and more. We should not have to choose between protecting our privacy from unjustified government surveillance and participating in modern life. Law enforcement should be no less required to obtain a warrant to view our search histories than to read the contents of our private letters or emails. The ACLU's Freedom of Information Act request provides an opportunity for the government to explain whether it thinks it needs a warrant to obtain our private search histories, or whether its practices are at odds with the requirements of the Fourth Amendment.