It's no secret that meta data collection by various authorities is really useful - who's emailing who, from what IP address and what time etc. This is all part of an email header when an email is sent and received. Normally you can't see this unless you know where to look.
An email header contains a lot of information and usually looks something like this.
Received: from fep14-example.com (fep14 [192.168.16.115])
by local-daemon (Example com Mail) with ESMTP id <0O4T005Z9GVKT720@local-daemon>
for email@example.com; Wed, 30 Mar 2016 09:01:25 +1300 (NZDT)
Received: from mxin3-example.com
(lb1-company.com [18.104.22.168]) by mx6.example.com (Example COM Mail)
with ESMTP id <0O4T00FC4GWX9060@mx6.example.com> for
firstname.lastname@example.org; Wed, 30 Mar 2016 09:00:35 +1300 (NZDT)
Received: from mail1.company.com ([22.214.171.124])
by mxin3-example.com with ESMTP; Wed, 30 Mar 2016 09:00:33 +1300
Received: from wmail1 (mail.company.com [192.168.42.147])
by mail1.company.com (Postfix) with ESMTP id B8959223634 for
<email@example.com>; Tue, 29 Mar 2016 16:00:32 -0400 (EDT)
Date: Tue, 29 Mar 2016 16:00:33 -0400
From: firstname.lastname@example.org <email@example.com>
Subject: This message you wanted
To: "firstname.lastname@example.org" <email@example.com>
At first glance it looks like a bunch of random stuff, but looking closer it gives a lot of information about who the email is from, when it was sent, the path it took to get to the recipient and when it was delivered.
But really, this is no-body's business but your own. Using EncryptUs you can not only hide the content of your emails, but you can also obfuscate (that's a fancy word for mask) the header information. EncryptUs has an option to completely anonymize the header of an email when it leaves your computer, and then re-assemble the header when it reaches the recipient.
Not only that, your email will be bounced around the world between different and random servers and the header constantly changing so it cannot be tracked or identified where it ends up. EncryptUs uses strong end to end encryption to guarantee safe passage of your confidential email messsages.
Not only that, when you use EncryptUs you don't need to change anything about the way you send and receive email - it's all automatic. Plus, EncryptUs is free to use.