Next you visit an airline website and you get a higher fare becuase of the knowledge that you have already booked a hotel in that city so they know what day you have to travel. What part of that do you believe is already here, and what part is dystopian future?
I'm against the whole idea of information as a commodity, and the ad business today is just that: it's customer information as a bulk commodity. I don't mind being shown ads I just don't want my information collected and used. You could argue that website owners actually give me something (the content) and want something in return (a payment or an ad impression), but I disagree with how the transaction takes place without my knowledge. Just use static image ads served from your domain, then my browser can't know it's an ad. It will be a "dumb" ad, but those have worked in magazines and bus stops since forever.