The cookies Google uses to secure and authenticate an user's Google account, and store his preferences, may be served from a different domain than the website the user is visiting, Google said on its support site. "The P3P protocol was not designed with situations like these in mind. As a result, we've inserted a link into our cookies that directs users to a page where they can learn more about the privacy practices associated with these cookies," it added.
Whetstone also referenced a Facebook statement on its website, that the P3P standard is now out of date and does not reflect technologies that are currently in use on the web, so most websites currently do not have P3P policies. "The organization that established P3P, the World Wide Web Consortium, suspended its work on this standard several years ago because most modern web browsers do not fully support P3P," it added.
Facebook social plugins are built and designed to protect privacy by providing users with social experiences on other websites without requiring any additional cookies to be set, the company said in a statement. "Therefore, our P3P policy is not intended to enable us to set additional cookies or to track users," it added.
Facebook said that P3P, which was developed many years ago, is not effective in describing the practices of a modern social networking service and platform. Facebook has instead posted a public notice describing its practices which is consistent with Section 3.2 relating to policies in the P3P specification, it said.
The section of the P3P 1.0 specification states that in cases where the P3P vocabulary is not precise enough to describe a website's practices, sites should use the vocabulary terms that most closely match their practices, and provide further explanation in a human-readable consequence field or policy.