Facebook has a decent explanation for why they do not use P3P in the headers for their Like buttons:
P3P CP="Facebook does not have a P3P policy. Learn why here: http://fb.me/p3p (URL redirects to http://www.facebook.com/help/?topic=p3p).
P3P CP="Facebook does not have a P3P policy. Learn why here: http://fb.me/p3p (URL redirects to http://www.facebook.com/help/?topic=p3p).
"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. As a result, the P3P standard is now out of date and does not reflect technologies that are currently in use on the web"
IE does support P3P - perhaps not completely, but to some degree.
the P3P standard is now out of date and does not reflect technologies that are currently in use on the web"
Actually, reading it in conjunction with the new Mozilla privacy icons shows it has held up fairly well.
I'm just troubled by the idea that Mozilla seem to be re-inventing the wheel a bit here.