P3P and Google's cookies
In some situations, the cookies we use to secure and authenticate your Google Account and store your preferences may be served from a different domain than the website you're visiting. This may happen, for example, if you visit websites with Google +1 buttons.
Some browsers require third party cookies to use the P3P protocol to state their privacy practices. However, 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.
c/o Google Inc.
1600 Amphitheatre Parkway
Mountain View, California, 94043