A link titled AskEraser will be featured on the site's home page and all search results pages, with a clear choice to signal whether the feature should be "On" or "Off" during a user's search requests.

"We take significant steps to protect any data that's stored in our servers, but for those people who want to take extra precautions, AskEraser let them take the issue completely off the table," Ask.com Chief Executive Jim Lanzone said in an interview ahead of Tuesday's launch.

When activated, AskEraser deletes all subsequent search queries and related information linked to a user's "cookies," or identifying information from their computers. The feature becomes available on Tuesday for U.S. and UK users, and will expand to global sites in 2008.

Earlier this year, Ask said it had changed its data retention policy to separate a person's search history from their identifying Internet information after 18 months. The company is part of Internet conglomerate IAC/InterActiveCorp.

The opportunity to stake out private space on the Web becomes more critical as Internet use grows more deeply embedded into daily life and as Web sites and advertisers seek information on user behavior to send them targeted messages.

Ask is working on its own products that take better advantage of Web usage patterns, on an anonymous basis, to improve the relevance of the search results it can offer.

"Hand in hand with that is getting people the option of not participating" when they don't want to, Lanzone said.