Sure. Though of course that means some functionality will be broken for all IE users with default privacy settings.

Sure, but in a fixable manner. I can always turn on third-party cookies if I like.

A faked P3P header breaks IE's privacy settings in a nonfixable manner.

Fixable for technical people, sure.

Not for the average user. The user who uses the default web browser. The user who uses IE.

If they can convince people to install Chrome Frame, I'm sure they can figure out how to tell people to enable 3rd party cookies. My guess is they'd have a lot harder time explaining why the user should do that.

This is silly. I highly doubt Google is having any luck convincing average users to install Chrome Frame. This is not a counter argument.

And yet they spent all that time doing it ... Seriously, who is Chrome Frame for if not the average user? And they inform you about it as soon as you visit google.com in IE.

I suspect you're right and the uptake isn't what they wanted, but that's not really a valid reason for them to work against the browser settings designed to protect a user's privacy.

What functionality would that be? Tracking what pages the visitor browsed via the +1 buttons?