Ewwww.... This is creepy.
However, it is also unsurprising. It is easy for anybody with decent reasoning skills to be able to see that this is just the logical consequence of what happens when people share so much of their information with social networks whose entire purpose is to learn more about you....and then to make this information available to other entities...
I think that this is one of the best points made in the article:
This is an app you should download to teach the people you care about that privacy issues are real, that social networks like Facebook and Foursquare expose you and the ones you love, and that if you do not know exactly how much you are sharing, you are as easily preyed upon as if you were naked.As someone who cares deeply about security and privacy issues, I hope that this app serves as an effective wake up call.