Think about it. If I know you, everything about you, I can sell directly to you. Not just things that are vaguely intersting to you, but to the most primal want you have. The key is getting an accurate image of who you are, tapping into the "I cant resist" part of your individual monkey brain. We all have somethings that we don't think rationally about,and if someone can map you down to you that point, then they have you. Your patterns on social media leak that data. The more sources, the more accurate they can construct "you."
The next step is biometrics. The kinect is a good example. Im betting that is looking to measure pupil dilation, heart rate, etc. if its not already. Looking at an ad and your heartrate goes up and pupils change? Time for these similar ones, ever deeper and deeper into you.
If I can do that, I can sell that info to a vender with an actual product, making myself very wealthy just moving data around. Its even better if Im also that vendor, like in microsofts case with games. Then I cut out the middle man and vertically integrate myself to the moon.