said by mmainprize:I do not know how they do it but i get e-mails with one or more addresses in the To: line but it is not my address listed. Like you stated it don't have to be there or was removed, and maybe it is a blind copy of some sort.
It is too late to edit my post, but add Google Mail to the list of very few providers including the "SMTP Envelope Recipient (RCPT TO:) email address in the headers.
Yahoo Mail:
X-Apparently-To: %me%@yahoo.com via 98.138.213.251; Thu, 01 Nov 2012 10:39:36 -0700
Google Mail:
Delivered-To: %me%@gmail.com
GMX Mail (.com is English, .net ist Deutsch; both have the same header stamp):
Delivered-To: GMX delivery to %me%@gmx.com
...
Delivered-To: GMX delivery to %me%@gmx.net
None of my other ESPs do this. If your ESP doesn't so stamp their email headers, you might request it. However, given the nature of SMTP, if it is in your mailbox, there was an SMTP "RCPT TO: <%your_email_address%>" command. SMTP servers don't "guess", they are as literal as any computer.