The W3C's Platform for Privacy Preferences (P3P) provides a standard way for web sites to communicate about their privacy practices (see for more details).  More and more companies like Microsoft, IBM, Dell, Yahoo, CNet, DoubleClick and many others, are implementing P3P to demonstrate corporate leadership on privacy issues, and, as a positive benefit, prevent IE 6.0 and some other browsers from blocking their cookies (see Internet Options -> Privacy tab).


What is in a P3P policy?  Company name and contact info, the types of collected data, how the collected data is used, mechanisms for resolving privacy disputes, etc. is a great site with information on how to make your web site P3P compliant, including P3P guiding principles document, links to P3P policy editors, and more.