hmmm wondering if there is a market for NNNN.io haven't seen many sales for number .io as of yet. it's usually the Chinese market that looks to letters and numbers of this nature but I usually only see .org .net.com..co.uk
Many thanks for your feedback...I'm seeing decent sales for young aged .io domains sold on flippa. I think there is a bit of jostling to secure them for the long term. Anyway, only time will tell.