Ask HN: What is the best ad platform to test a mobile landing page?

After interviewing multiple parents, validating the problem I thought existed really does I know want to validate that parents will signup/download the app I'm planning to build.

This is the landing page I created using LaunchRock: http://kiddiz.launchrock.com/ (still work in progress)

1. What is the highest ROI mobile ad network out there? 2. Does anyone know an ad network that allows me to see the monthly active users of specific apps and then advertise specifically there?

Thanks

P.S If you are a parent and are willing to be interviewed by phone/skype - drop me an email: eytanlevit@gmail.com