Yeah, I think it is not appropriate to sell their emails just like that!!!
Yes, you had their consent. But that was before & to quote
CjMapope -
you have "consent" thru fine print noone reads :/
if any of those users were asked right now if they consented to their personal data being sold to the highest bidder i assure you they would most likely say "fuck no"
screw you man, i have left a neg to the kind of person you are. (keep in mind trust ratings are unmoderated and user-generated)
So if any of these individuals had predicted that you will do this kind of act, I believe for sure that no one had signed up in your IPO in the first place.