How does your service works? is it base on users session? if different users visits your site at the same time they will get different different emails or not?
And do you have logs all of this emails user's receive and the email of course? I bet this site will be useful to those people who doesn't want to give their personal emails to some unknown websites they're trying.
I do not keep a log of what everyone receives it auto-deletes every log every 25 min.
For your protection and mine Ive set a cron job to delete all log files every 25 minutes via " find /var/log/* -exec cp /dev/null {} \; " It does use a simple cookie for user sessions, so the emails are always unique.
It would be useful for places you wanted to try out. The TOS has more information.