P3P….

Platform for Privacy Preferences aka P3P.
An intriguing concept.

the W3C has a project to implement machine readable privacy policy on websites.
The idea being to have the browser compare the published policy to the user’s preferences.
when there is a mismatch to alert the user that privacy policy on this site does not match the user’s settings.

the specification for it is here:

http://www.w3.org/TR/P3P/

a deployment guide:

http://www.w3.org/TR/p3pdeployment

and references for p3p implementations:

http://www.w3.org/P3P/implementations