Google will be changing the way it stores it’s logs in the coming months. They will now start anonymizing the way it stores searches by it’s users. Unless forced to by law enforcement, they will not store data that can narrow down what an individual searched for. From the Google blog:

When you search on Google, we collect information about your search, such as the query itself, IP addresses and cookie details. Previously, we kept this data for as long as it was useful. Today we’re pleased to report a change in our privacy policy: Unless we’re legally required to retain log data for longer, we will anonymize our server logs after a limited period of time. When we implement this policy change in the coming months, we will continue to keep server log data (so that we can improve Google’s services and protect them from security and other abuses)—but will make this data much more anonymous, so that it can no longer be identified with individual users, after 18-24 months.