Ask HN: What do you want to see built?
I'd really like a service that allowed me to pay my recurring bills (rent, utilities, etc.) with my credit card. What about you guys?
With a small financial incentive people would be motivated to reply to your mail too. You could ask anyone no matter how rich, some questions and be sure to get an answer if when he/she has agreed to get only paid messages he/she can only collect money if he/she actually answers.