When we first created Domainr (then domai.nr, now domainr.com) back in 2008, we needed a list of “zones under which domain registrations were somehow possible.” E.g. not just the root zone list from IANA, but all the .co., .edu., .net., etc. variants. We found what we could from Wikipedia, and used Mturk to find the rest from registry websites, etc.

It wasn’t perfect, but it didn’t need to be. We essentially needed a “good enough to start with” dataset that we could refine going forward. It got the job done.