atlrus - 12:30 am on Aug 18, 2013 (gmt 0)
I think the point was lost in all this technical discussion. And the point being the quote:
a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties
Today it may be for spam filtering, but tomorrow we could find out something different. Don't know about any of you, but I do expect privacy when I send an email or snail-mail. You know who doesn't expect privacy when communicating? Prisoners. Google telling you in your face that your emails will not be private and you choosing to continue using the service is your problem.
I personally could care less in this case, since I opted out of gmail the minute it was understood that they will read your emails for the purpose of advertising.