Early this morning, Yahoo announced that it will be reducing its data retention period to 90 days, a dramatic drop from its prior 13-month limit on keeping user search data.

Yahoo's Vice President of Policy and Head of Privacy Anne Toth posted on the official Yahoo Blog this morning, "Our content and advertising customization will remain cutting-edge and relevant to your interests -- but the data we use to provide those services will only be kept for as long as we really need it."

The search engine's privacy policy currently states: "Yahoo automatically receives and records information from your computer and browser, including your IP address, Yahoo cookie information, software and hardware attributes, and the page you request. Yahoo uses information for the following general purposes: to customize the advertising and content you see, fulfill your requests for products and services, improve our services, contact you, conduct research, and provide anonymous reporting for internal and external clients."

Under the revised rules, Yahoo will anonymize search log data, page views and clicks, as well as ad views and clicks. Yahoo did not expressly state this morning what will happen to IP addresses or cookies, but according to the Associated Press, portions of IPs will be removed, and cookies will be altered.

Two weeks ago, Microsoft publicly stated it would be open to the idea of anonymizing its search data caches after six months -- a reduction from the previous 12-month policy -- but only if Yahoo and Google stated their willingness to do the same. Google's take on the challenge has yet to be heard.

Competing services from Google and Microsoft have both altered their data retention policies, but Yahoo's proposed 90 days would be the shortest by far, barring exceptional circumstances. Instances of fraud, security breaches, and legally binding situations would lead Yahoo to hold personally identifiable search data for longer than 90 days.