Este vorba de etichetele din header-ul emailului. Daca are eticheta "To" atunci clientul tau de e-mail iti va afisa adresa destinatie (a ta). Daca nu are "To" clientul de e-mail nu iti afiseaza adresa destinatie, insa daca te uiti in headerul e-mailului vei vedea adresa ta la "Envelope-to" (parca am vazut si varianta cu "Deliver-to"). Uite cum apare la mine:

Cod:
Return-path: <whdeekhf@motodirect.de>
Envelope-to: contact@a****.net
Delivery-date: Tue, 10 Oct 2006 09:12:09 -0500
Received: from host79-63.pool8250.interbusiness.it ([82.50.63.79]:2017 helo=host51-195-dynamic.55-82-r.retail.telecomitalia.it)
 by gator130.hostgator.com with esmtp (Exim 4.52)
 id 1GXIKx-0002yQ-5G
 for contact@a****.net; Tue, 10 Oct 2006 09:12:09 -0500
Received: from [165.166.31.199] (helo=[06425314583])
        by host51-195-dynamic.55-82-r.retail.telecomitalia.it with smtp (Exim 4.60 (FreeBSD))
        (envelope-from <whdeekhf@motodirect.de>)
        id QYI1-MAWqbH3-XUm
        for contact@a****.net; Tue, 10 Oct 2006 16:12:21 +0100
Received: from motodirect.de (53186380586 [6734247730])
        by mail2.nwe.de (Qmailv1) with ESMTP id H5QGW6P2
        for <contact@a****.net>; Tue, 10 Oct 2006 03:52:07 +0100
Date: Tue, 10 Oct 2006 03:52:07 +0100
From: "Fred" <whdeekhf@motodirect.de>
X-Mailer: PObox II beta1.0
X-Priority: 3
Message-ID: <1312512665.2006101003520744580@motodirect.de>
To: contact@a****.net
Subject: [VAR114]
X-Antivirus: AVG for E-mail 7.1.407 [268.13.1/469]
Mime-Version: 1.0
Content-Transfer-Encoding: 7bit
Content-Type: text/plain; charset=iso-8859-4