A DNS service with any type of free tier of service does not work. They have been tried dozens of times before (including by me), and never work out over the long term.<p>Your number one problem will be abuse. 50% of your user base will be the hacker/hobbyist types you expect, the other 50% will be people who can't get DNS service elsewhere (MLM/Ponzi schemes, child porn, jihadist forums and propaganda sites). These types of sites will generate tons of inbound complaints which you need to deal with, as well as massive DDoS attacks which you will need to sink to avoid service disruptions (think $100k+ in hardware plus bandwidth costs).<p>If you are crazy enough to move forward, you should reach out to dnsbl.org, its a shared database of domains to deny service to.