Sometimes (just sometimes), this is why GMail psyches me. Look at this screenshot. It read the words in my email and is trying to tell me why this email is important. Well, there is more. If you dont think so, it is asking you to teach GMail why it is not so important.
Not only is it analyzing my emails, and also trying to figure what is important and what is not to me.
Having been part of the Online Advertising business for a brief while, I can see why this is super important for Google. It helps in better targetting ads for me. But it still creeps me out.