The "a person has no legitimate expectation of privacy in information he voluntarily turns over to third parties" quote has been massively taken out of context by everyone who is covering this story.<p>The overall case appears to be about people complaining that Google scanning their emails and showing contextual ads is a privacy violation.<p>Most of this document is an explanation of why that shouldn't hold (Gmail users agreed to this when they signed the ToS, automatic scanning is essential for things like spam filtering and full-text search, legislating against this will kill innovation in online services etc).<p>The section that contains the "expectation of privacy" quote is in reply to part of the case which suggests that, while Gmail users may have accepted the ToS, non-Gmail users who send an email to a Gmail user have NOT accepted that ToS and hence are having their privacy violated.<p>The counter-argument presented is that, if you send a letter to someone and they allow their assistant to open it, you shouldn't be surprised by that. The analogy is that if you send an email to someone who has chosen to use a specific email provider, and that email provider automatically scans your email in some way, you shouldn't be surprised either.<p>As I read it, the "third parties" in the troublesome quote aren't Google themselves - they are the recipients of your email who happen to be using Gmail. You've turned over your information voluntarily to the recipient of your email, they can then chose to allow it to be automatically processed by the email provider they have an agreement with (without this violating your expectations of privacy).<p>I call bullshit on the whole story.