IDcide's Privacy Companion
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Privacy Companion is a free browser add-on that alerts you when and where
you may be followed on the web and by whom, allowing you to block third party
trackers while still receiving personalized services from the site you are
visiting. IDcide's Privacy Companion deals with both
incoming and outgoing cookies, uniquely distinguishing between site cookies and
third party cookies. Privacy Companion protects from third party trackers that
transmit cookies through banners and Web-Bugs, and from accidental Data Spills
by blocking referral information.
This is a beta product and only support IE 4-5.01 at this time.