User worries are driving search firms to let people manage how much data they reveal when they visit the sites.
Top search engines are storing user data for less time
The top four search sites, Google, Microsoft, Yahoo and Ask, have unveiled plans to cut how much data they hold and how long they store it.
Going furthest Ask said it would let users search without surrendering any data about themselves and their PC.
At the same time Microsoft and Ask have called for an industry-wide deal to draw up standards on user privacy.
The rush to improve privacy policies was started by Google in March
when it announced it would start deleting the final parts of the individual address it collects from each user's computer after 18 months.
Google said it would only keep data for longer if legally compelled to do so.
Earlier this month the firm announced that its cookies would expire two years on from a user's last visit. Prior to the policy change they were set to last until 2038.
A cookie is a tiny text file that huge numbers of websites, including the BBC, use to track users and record how they like to use a particular site.
Microsoft is expected to make a similar announcement to separate the identifying address and other data from searches after 18 months. The information will be held for longer if users request it.
Yahoo said it would delete identifying addresses and cookies after 13 months unless users want the data held longer or law enforcement agencies require it to store the information for longer.
Ask is taking the most radical step by unveiling plans for a tool called AskEraser which, it claims, will let people tune whether data is gathered about them on a search-by-search basis.
The tool is expected to be available in the US and UK by the end of 2007 and in other nations soon after that.
Following the announcements Microsoft and Ask released a joint statement calling on search firms to draw up shared standards that will define what data is collected, what is done with it and how it is used to drive advertising.
"People should be able to search and surf online without having to navigate a complicated patchwork of privacy policies," said Peter Cullen, Microsoft's chief privacy strategist, in a statement.
Doug Leeds, vice president of product management at Ask.com, said: "Anonymous user data can be very useful to enhance search products for all users, but people should have access to privacy controls based on their level of comfort around the storage of their search data."