America's top four Internet companies -- Google, Yahoo, AOL and Microsoft -- promise they will protect the personal information of people who use their online services to search, shop and socialize. But a close read of their privacy policies reveals as much exposure as protection. The massive amounts of data these companies collect -- which can include records of the searches you make, the health problems you research and the investments you monitor -- can be requested by government investigators and subpoenaed by your legal adversaries. But this same information is generally not available to you.

The risk is that personal information that can be traced to you will at some point be provided to someone else, like the 20 million AOL searches that were published on the Internet at the beginning of August and are now causing random AOL users to admit that they looked for ``movies for dogs'' or ``welley shoes.'' Two months ago, the Mercury News began asking the Big Four Internet companies to clarify their privacy policies. The newspaper wanted to know precisely what information was recorded when someone made a date on Yahoo, sought help for addiction on Microsoft's MSN or plotted their daily peregrinations on Google Maps.

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