Cool, email support@intromaker.com from your account email and I'll delete you.
(Which is the same offer I made to everyone else in lieu of an unsubscribe button.)
I did weigh whether to send a notice or not, and for me it came down to emotion more than economics. My thinking:
It'll end up costing a few hundred dollars to send it out. A lot of users have probably forgotten what IntroCave is or don't need it any more, and hopefully they'll request account deletion (hundreds of people did). I expected to generate approximately $0 in sales from the email, but if I can save even a handful of users from typing in the old domain, getting redirected to the new domain, wondering WTF, and bouncing -- that seemed worth it.