Google will delete search identifiers after two years

Google currently stores search terms along with the internet protocol (IP) addresses which could be used at a later date to help to identify the people behind a query.

The company has said that it will now delete the IP addresses after between 18 and 24 months. It will continue to store the search information for as long as it deems it useful.

"When you search on Google, we collect information about your search, such as the query itself, IP addresses and cookie details," said a Google blog written by the company's privacy lawyer in Europe, Peter Fleischer, and its deputy general counsel Nicole Wong.

"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. We will continue to keep server log data but will make this data much more anonymous, so that it can no longer be identified with individual users, after 18–24 months," said Fleischer and Wong.

Google said that its decision was taken after consultation with privacy groups in Europe and the US. Washington's Center for Democracy and Technology welcomed the move.

"This is an extremely positive development," Ari Schwartz, deputy director of the CDT, told the BBC. "It's the type of thing we have been advocating for a number of years."

The search engine firm said that it was retaining logs for up to 24 months to comply with data retention laws, and that it may have to extend the limit if other laws are passed which demand longer retention.

The EU Data Retention Directive mandates that countries pass laws by later this year that make it compulsory for service providers to retain certain customer data for between six months and two years.

The Directive affects phone, mobile phone and internet service providers, though ISPs can request for its implementation to be deferred in relation to them until 2009.

"By anonymizing our server logs after 18–24 months, we think we’re striking the right balance between two goals: continuing to improve Google’s services for you, while providing more transparency and certainty about our retention practices," said Fleischer and Wong. "In the future, it's possible that data retention laws will obligate us to retain logs for longer periods."