Sick of trying to justify its data retention policies to the privacy police, particularly the European privacy police, Google’s lawyers said late Monday on the company’s official blog that it was cutting the time it holds user-identifiable information from 18 months to nine.

When the new policy will take effect is unclear.

Google’s only making the concession because its “engineers developed methods for preserving more of the data utility while also anonymizing IP addresses sooner.”

It says, “We haven’t sorted out all of the implementation details, and we may not be able to use precisely the same methods for anonymizing as we do after 18 months, but we are committed to making it work.”

In March of 2007 when public opinion and regulatory concerns forced Google to anonymize its vast data banks after 18 months, it complained that the policy “sacrificed innovation” (for which read its business plan) and shortchanged search quality and security.

Contemplating nine months, it continues to say the same thing: “While we’re glad that this will bring some additional improvement in privacy, we’re also concerned about the potential loss of security, quality and innovation that may result from having less data. As the period prior to anonymization gets shorter, the added privacy benefits are less significant and the utility lost from the data grows. So it’s difficult to find the perfect equilibrium between privacy on the one hand, and other factors, such as innovation and security, on the other.”

Separately Google addressed the issue of the Suggest facility in its newfangled Chrome browser as well as in Google Search, Google Toolbar, Firefox, and the Google Search application on the iPhone, the widgetry that anticipates what you’re looking for before you’re finished typing. Sort of like your mother.

It says it’s only going to hold the data it collects for 24 hours.

According to Google’s operations senior VP Urs Hölzle, “To provide its recommendations Google Suggest needs to know what you've already typed, so these partial queries are sent to Google. For 98% of these requests, we don't log any data at all and simply return the suggestions. For the remaining 2% of cases (which we select randomly), we do log data, like IP addresses, in order to monitor and improve the service.

“However, given the concerns that have been raised about Google storing this information – and its limited potential use – we decided that we will anonymize it within about 24 hours (basically, as soon as we practically can) in the 2% of Google Suggest requests we use. This will take a little time to implement, but we expect it to be in place before the end of the month.

“All data retention is a balance between user privacy and trust on the one hand, and security and innovation on the other. In the case of Google Suggest we decided it's possible to provide a great service while anonymizing data almost immediately. But in other cases – such as our core web search – storing data like IP addresses for a time is crucial to make improvements to search quality, improve security, fight fraud and reduce spam.”