Interesting product. As a mobile app developer, I would very much like to know where my installs are coming from. This'll allow me to know if marketing efforts are paying off or not.
Not sure if I would pay for this though.
As a side note, since I have an app that ties heavily with human to human interaction, I would be very interested in knowing which social channels my in-app installs are coming from. I would much rather tune my virality channels to acquire users than pay to acquire users.