Yahoo Inc. said it would begin keeping records of its users' search engine queries for at least 18 months, abandoning an earlier policy in which it kept data for much shorter periods.
The retention of search term histories, which can encompass personal topics such as medical conditions or financial issues, has long been a tense topic in debates over digital privacy.
Yahoo said Monday that the decision was made to keep pace with online competitors.
"Over the past several years it's clear that the Internet has changed, our business has changed, and the competitive landscape has changed," Anne Toth, a policy executive at Yahoo, wrote in a blog post. "We have gone back to the drawing board to ensure that our policies will support the innovative products we want to deliver for our consumers."
It was also Toth who, in December 2008, said that keeping the data for only three months would set Yahoo apart from its competitors and build trust with the company's users.
But since that announcement, Yahoo's share of the search business has dwindled, dropping to 16% in March from 20% in late 2008, when it instituted its three-month retention policy, according to Web ratings firm ComScore Inc.
Microsoft Corp. said that after 18 months it removed information from search logs that could identify users, including IP addresses — the unique code that each Internet-connected computer uses to send and receive data.