If you want to get detailed information about how Web sites use your personal data, and you want to get it quickly, then you need to listen to a little bird--the Privacy Bird.

A free plug-in from AT&T for Internet Explorer 5 and later versions, Privacy Bird allows you to specify your privacy preferences regarding how a Web site stores and collects data about you. If a site's policies meet your requirements, a small green bird icon in the browser's title bar emits a happy tweet after you have loaded the page. But if the site does more with your information than you've said you'll accept, the bird icon turns red and chirps a shrill warning when you first load the page. The bird doesn't block the site; it only alerts you that you may not like what the site does with your information.

With a couple of clicks, you can see what a site plans to do with your data. Even at the lowest privacy threshold, I noticed, the bird was alarmed when I visited Yahoo.com, for example. I clicked on the bird's summary of Yahoo's privacy policy and found that, among other things, Yahoo "may use health or medical information for marketing" and "may contact you to interest you in other services or products and does not allow you to remove yourself from marketing/mailing list." (Full disclosure: PC World provides some content to Yahoo.)

The idea for the bird hatched at AT&T Research, which got involved when programmers at AT&T and many other companies began crafting the Platform for Privacy Preferences, or P3P.

P3P gives Web sites a standardized, simple way to disclose how they collect, use, and distribute personal information about their visitors. Specialized software can automatically query a site's P3P policy. Internet Explorer 6 uses P3P to give users fine control over which sites may set cookies. But the browser can't give you any information about how sites will use data entered into registration fields, shopping forms, or message boards.

That's where Privacy Bird earns its wings. Since its quiet launch last spring, thousands of people have downloaded the software. According to Lorrie Cranor, the AT&T researcher who headed the Privacy Bird project, about a third of the top 100 most-visited sites on the Web--including Expedia.com, Microsoft.com, and About.com--have in place the P3P policies the plug-in needs to operate. Unfortunately, that leaves another two-thirds of the largest sites (as well as many other sites, including PCWorld.com, for now) at which the Privacy Bird flashes yellow--a signal indicating only that the site has no posted P3P-compatible privacy policy.

Cranor says that completing the forms and creating the P3P files for an average-size site can take an hour or two; but because a posted privacy policy has legal implications, the process can take considerably longer for larger, more complicated sites--especially sites with order forms.

The Privacy Bird is already a useful tool. As more sites create P3P policies, it will become indispensable for cautious surfers.

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