I'm not entirely sure how this isn't stalking. This woman saw a man on the subway and now implores the city to find this perfect love for her. I understand this is an art project and the 'mystery man' could very well be her real boyfriend; but, if roles were reversed and this was a dude hunting down the perfect woman the police would be involved.
I applaud the effort and subverting the media for use as an extension in your art project. Of course, I really, really hope that's all this is. If successful, I sense eHarmony or OKCupid trying to do a similar ad ploy. Why? Because I'm jaded.
For my contribution, I present my own art piece: