Google’s privacy policy (1) describes exactly what information the site collects about its users. The policy lists seven categories of data that may be recorded when people use Google:
1. Information provided by users when signing up for Google accounts or other services. This information could include names, e-mail addresses, account passwords, and credit card numbers. Google may cross-reference this data with other Google services and/or third party sites.
2. Google uses cookies that uniquely identify a user’s browser to track the user’s preferences and searching habits. Users can disable cookies, but Google’s services (and those of other websites) may not work as a result.
3. Whenever a user enters a search term, Google’s servers automatically record data, which is then stored in server logs. A typical server log entry looks like this example given on Google’s privacy FAQ page:
123.45.67.89 – 25/Mar/2003 10:15:32 – http://www.google.com/search?q=cars – Firefox 1.0.7; Windows NT 5.1 – 740674ce2123e969
The first number is the user’s Internet protocol (IP) address. Next are the date and time of the search, and next is the URL generated by the search, which shows what the user typed into the search box (“cars” in this case). After that is the user’s browser type and version, operating system, and finally a string of digits that is stored in the cookie Google created to uniquely identify the user’s particular browser. (2)
4. Google retains e-mails and other communications that people send to Google.
5. Information that users provide to affiliated sites may be sent to Google.
6. When users click on links, including search results and advertisements, Google can tell which users clicked on which links.
7. Finally, sites that are unaffiliated with Google, but which Google links to as search results or for some other reason, may also collect personal data, and Google’s privacy policy does not apply to them.
#2, #3, and #6 are of the most concern for my blog, since they apply most to people who are unknowingly providing Google with data. What can Google figure out with this data? Because Google tracks users with both cookies and IP addresses, it is easy for them to compile a list of your entire search history.
An IP address is a string of numbers that each user gets from his or her Internet service provider (ISP) in order to be able to connect to the Internet. ISPs include companies such as Comcast, AOL, and EarthLink, as well as workplaces and universities that have their own wireless networks. Many wireless networks, such as those at homes and businesses, give users a static IP address, meaning that the IP address is the same every time the user browses the Internet. By using databases that list IP addresses by geographic location, Google is able to determine where each user is located, often down to a particular city or town. (3) For workplace wireless networks, Google can usually see the domain name of the employer and tell what company the user works for. Other wireless networks (including Harvard’s, I believe) give users changing IP addresses. In these cases, although Google can usually figure out the user’s university or other ISP, it is difficult for Google to compile a single user’s search history.
This is where cookies come in. Thanks to cookies, Google can keep track of individual users even if they have a changing IP address. Although it is possible to disable cookies, it is inconvenient, as many websites don’t function properly without them. Additionally, less technologically savvy people may not know how to disable cookies, or even what a cookie is. So unless you have a changing IP address and disable cookies, Google can compile a record of your entire search history. Such a record includes, among other things, all the terms you have searched for, what time you did each search, and what search results and ads you clicked on. This reveals, to a great extent, what your interests are, what you think, and how your mind works.
Sources:
1. Google Privacy Policy <http://www.google.com/intl/en/privacypolicy.html>.
2. Google Privacy FAQ <http://www.google.com/intl/en/privacy_faq.html>.
3. Google Search Term Demonstration from Google Watch<http://www.google-watch.org/cgi-bin/urldemo.htm>.