Quick poll to understand how much everybody knows. I've probably worked more on email than any other section of running servers. No email = no validated users. If you do vote, share what you do know already. If you have had any difficulties or have any questions about how email generally works. My own skill level is taking an existing email package and trying to get the best out of it. And from a sys admin pov monitoring ingree/egress of email for problems. Biggest difficulty is always the success of delivery. If your email succeeds great but how quickly is just as important. If you or I wait for email to be delivered we usually get frustrated trying to validate a new account.