Microsoft on Tuesday said that it would change the data retention policy of its Bing search service fairly dramatically and called on market leader Google to do the same. Microsoft, like Google, currently retains IP information with search results data for 18 months, a practice both companies claims helps improve search accuracy. But Microsoft will soon retain this data for only 6 months.

"Specifically, we are reducing the amount of time we store IP addresses from searchers to 6 months," Bing privacy manager Reese Solberg wrote in Microsoft's official Bing Community Blog. "When Bing receives search data we do a few things: first, we take steps to separate your account information (such as email or phone number) from other information (what the query was, for example). Under the new policy, we will remove the IP address completely at 6 months, instead of 18 months."

The change will occur over the next 18 months, Microsoft says, a time frame that is required to ensure the data storage is secure and tested.

The big question is why Microsoft is making such a change. Previously, the software giant claimed that it needed the time to further hone the accuracy of its search results. In today's blog post, however, Solberg noted that the change provides "the right balance between making search better for consumers and providing greater protection for the privacy of our users."

According to the software giant, the changes should answer criticisms from EU-based privacy advocates and possibly head off future regulation there. In 2008, the Article 29 Working Group, a panel of privacy regulators from every country in the European Union, asked Microsoft, Google, and Yahoo! to separate IP address information—which could be used to identify individual users—from search results data after 6 months. Microsoft's original response, in 2009, was to make IP address information anonymous after 6 months, but not separate the data. So this new change means that Microsoft will belatedly adhere to the regulators' request, albeit ahead of the competition.

"We support what the Article 29 Working Group is doing," Microsoft Vice President and General Counsel John Vassallo said. "That is why we are making this change. We call on our competitors to do the same."

In related news, EU regulators set a deadline of February 19 for it to examine Yahoo! and Microsoft's proposed search deal. The two companies announced their plans in July 2009 and said at the time that they expected it to pass regulatory muster around the world sometime in 2010