I'd like to know an approximation of what that customer would be worth to them in monetary terms per day or year, based on things like the ads they focus towards them and all other other acquired data (Habits, trends, realtime location and history) that they can sell on to third parties.

I'd be very keen to hear from people in Marketing, IT and data mining roles or anyone else who has ever dug into this kind of thing... A tank of thank in advance!