Responding to public concerns that major search engines are storing user data for too long, MSN and Yahoo! have said they will update their privacy policies, according to a report in CNET News.

MSN said it will delete data after 18 months and also store search terms in a separate database from account information that personally identifies the user.

Yahoo said it plans to limit its data storage to 13 months.

Both companies said they would give the user the option of consenting to longer data storage times.

Late last week, Ask.com said it would allow people to search the internet privately, while Google said its cookies would expire after two years. Google had previously set its cookies to all expire in 2038.

The search engine industry has been under some heat of late with respect to privacy, with privacy advocates calling on firms to shorten data storage periods and increase transparency. In May, the issue came under the scrutiny of federal regulators, when the Federal Trade Commission launched a probe into Google's acquisition of DoubleClick. Although the deal has yet to be approved, Google has said that it is confident regulators will not view the acquisition as being hostile to user privacy.