Brian Tillman said:
Why? Outlook by default keeps a copy of every message you send
already.
Some users don't trust their mail server to actually perform the send
operation. They want a double-check by getting back a copy of their
own message but from the mail server. This is to verify if the mail
server ever did send out any copies of their message. It does result
in the sender having 2 copies: one in the Sent Items folder (or other
folder if a reply and Outlook configured to save there) and another
from their mail server. The copy in the Sent Items folder provides no
proof that the mail server ever sent a copy of your e-mail from there.
Most of us trust that if we get back an +OK status that the mail
server will eventually send our e-mail but we won't know for sure or
when it does the send. I have been stuck trialing some e-mail
providers where I could see that they were batching up outbound
e-mails and sending them out at 1 to 4 hours intervals hence the delay
to the recipients. I could only see that delay by having a copy of my
own e-mail as the mail server sent it to check the Received headers.
The copy in Sent Items folder does not prove that your e-mail actually
got sent or when it got sent, only when your own e-mail client made
its own copy based on getting a good status back from the mail server
that it *received* your e-mail which has nothing to do regarding when
it actually *sent* your e-mail.
Some users are more paranoid than others. Sometimes there is good
reason for the paranoia. ("You are not paranoid if there really are
people out to get you.")