Alex Fowler, a technology and privacy officer for Firefox maker Mozilla, said the ``Do Not Track'' tool will be the first in a series of steps designed to guard privacy. He didn't say when the tool will be available.
Google Chrome users can now download a browser plug-in that blocks advertisers but only from ad networks that already let people decline personalized, targeted ads. According to Google Inc., these include the top 15 advertising networks, as rated by the research group comScore, a group that includes AOL Inc., Yahoo Inc. and Google itself.
The next version of Microsoft Corp.'s Internet Explorer browser, which is still being developed, will include a similar feature, though people will have to create or find their own lists of sites they want to block.
Google and Mozilla, however, are developing tracking-protection tools that will work automatically once people decide to turn on that privacy feature, that is.
Microsoft, Google and Mozilla's promises of stronger privacy comes on the heels of government complaints that online advertisers are able to collect too much data about people in their quest to target ads.
Last month, the Federal Trade Commission recommended the creation of a ``Do Not Track'' tool that would invite consumers to restrict advertisers from collecting information about them, including the websites they visit, the links they click, their Internet searches and their online purchases.
Meanwhile, the Commerce Department last month called for guidelines that would require online advertisers to warn consumers what information about them they are collecting and how they plan to use it. Consumers, the department said, should be able to ``opt out,'' or decline, some or all of that data collection. And if companies do collect information, they would be required to store it securely.
Google product managers Sean Harvey and Rajas Moonka said the new Chrome tool will allow for more permanent ad blocking. Before, opt-out settings were typically stored through small files known as cookies; when users clear cookies, however, the opt-out settings get erased, too. Another benefit is that the new tool allows users to opt out of all participating ad networks at once, rather than one at a time.
Google eventually hopes to develop a similar plug-in for other browsers as well, Harvey and Moonka added.