Google's data retention policy emerges
To personalise the services it offers, Google retains user data such as search histories and as well as the Internet Protocol (IP) addresses and other digital identifiers that enable the company to link search queries to the specific computer where they were generated. Until March 2007, the company kept this data indefinitely. At that point, it announced that in response to privacy advocates' concerns it would begin anonymising the data after 18 to 24 months. While some welcomed the change, critics complained that the new policy risked undermining their efforts to combat law enforcement demands that online services retain search records and other data for long periods of time.
After continuing pressure from privacy advocates, policy makers, and regulators, particularly in Europe, in September 2008, Google announced it would shorten the time to anonymisation to nine months, though it noted that it was reluctant to do so because retaining data allowed it to offer users a better service, prevent fraud, and improve security.
https://www.nytimes.com/2007/03/15/technology/15googles.html
https://bits.blogs.nytimes.com/2008/09/09/google-tightens-data-retention-policy-again/
https://googleblog.blogspot.co.uk/2008/09/another-step-to-protect-user-privacy.html
Writer: Miguel Helft; Peter Fleischer and Jane Horvath and Alma Whitten
Publication, New York Times, Google blog