In the company i work in our boss has told us to stop using gmail for any kind of company communications including not using google apps anymore. He said that he was told that with the new Google policy they're reading user e-mails (we all knew that) and that they will use that info to see if a user is trying to buy traffic, linksharing, etc, you know, the kind of seo optimization / traffic stuff that google doesn't likes. And he said that that will affect the ranking now.
More in detail: according to him, an e-mail from a business partner telling me to buy sites for traffic, will impact my seo ranking the same way that people exchanging links through e-mail does.
My opinion is that this is paranoid. Yes Google could do it, but they would need lots of logic to detect possible emails about user conversations about buying traffic. But more, no sofware can detect that with accuracy, only a human can then somebody would have to read the e-mail at google's. And that is privacy invasion. And not only that, i can't imagine the amount of people reading who-knows-how-many e-mails.
Plus, like i said it would too close to the privacy boundary. Why would google invest millions in this while they can easily improve their algorithm (like penguin) ?
What do you think. Is is highly likely ?