Microsoft is joining Ask.com in offering Web surfers a way to use its search engines anonymously, and the two companies are now calling on the search and online advertising industry to develop a common set of privacy practices.

By year's end, Microsoft will give users a way to search anonymously on its Microsoft Windows Live Web sites, and it will also implement a new data retention policy that after 18 months will scrub all search query data of any information that could be used to identify the searcher.

"We think that we as an industry ought to take a look at ways to further enhance privacy protections," said Microsoft Chief Privacy Strategist Peter Cullen. "We're really trying to make sure that people always have the ability to have a trusted experience."

These steps are similar to those taken by Ask.com last week and are part of an effort to create industry consensus on privacy practices, Cullen said.

When visitors use Microsoft's Windows Live search engine, Microsoft stores the search queries along with some information on the person doing the searching in order to provide them with targeted advertising. Like all the major search providers, Microsoft doesn't associate names or e-mail addresses with this data, but it does keep IP (Internet Protocol) addresses and some other identifying information, such as the zip codes of Windows Live users.

Privacy advocates are concerned that this data could be misused.

"Search terms are often about drugs, they're about sex and they're about rock and roll," said Peter Swire, a law professor with Ohio State University who was the White House's Chief Counselor for Privacy under the Clinton administration. "There are a lot of people who are feeling that they're doing a private exploration and wouldn't want their search terms as part of their permanent record."

Last year, AOL researchers inadvertently illustrated how this data could be misused when they posted data on about 650,000 searches made on the company's Web site. New York Times reporters were able to track down one of the searchers based on the information in the database.

Ask.com and Microsoft's announcements put pressure on Google to improve its privacy practices, Swire said. Google retains part of the IP address associated with searches and has not promised to provide anonymous searching, he explained.

It is becoming even more important for companies to safeguard consumers' privacy as the online advertising and search industries consolidate, Swire said. Both Microsoft and Google have made major moves in this space over the past few months with their planned acquisitions of aQuantive and DoubleClick.

More pressure is coming from the European Union, which has placed limits on the amount of time search companies can retain this type of data and is reviewing Google's DoubleClick acquisition.

Microsoft and Ask.com will invite privacy advocates and Internet search and advertising companies such as Google, AOL, and Yahoo to come together and more clearly explain how the industry will handle privacy. "The first step is, we'll be in contact with all the other players in this space and talk about what a summit might look like," said Cullen. "We're very happy to host it, if that's the answer ... both Microsoft and Ask.com think that this is the time to make this happen."

The two companies expect to report on the results of this outreach by September. That's right around the time that the U.S. Federal Trade Commission (FTC) is expected to host a workshop discussing these same issues, Swire said. "Now we're getting public debate and corporate debate on best practices. And the FTC will be trying to push that this fall."