Microsoft moaned that Google was blocking a feature in IE which stops cookies from tracking users.
IE by default blocks third-party cookies unless a site presents to the browser a P3P Compact Policy Statement describing how the site will use the cookie and pledging not to track the user.
Google has defended its actions claiming that P3P is impractical to comply with while providing modern web functionality such as cookie-based features.
Google took advantage of a technical feature in the P3P specification which was there to leave room for future advances in privacy policies. The P3P specification states that browsers should ignore any undefined policies they encounter. But P3P compliant browsers interpret Google’s policy as indicating that the cookie will not be used for any tracking purpose or any purpose at all
Google’s senior vice president of communications and policy, Rachel Whetstone told PC World that Microsoft’s policy was “widely non-operational”.
She said that new cookie-based features are broken by the Microsoft implementation in IE, Google said. Stuff like Facebook’s “Like” buttons and the ability to sign-in to websites using a Google account are tiggered by P3P.
She added that it was well-known among developers that it was impractical to comply with Microsoft’s request while providing this web functionality.
Google has been open about its approach on P3P, and so have other websites including Facebook.
That was not even dreamed of when the P3P protocol was thought up. So Google had to inserted a link into cookies that directs users to a page where they can learn more about the privacy practices associated with these cookies.