Coen Vermeer

List-unsubscribe header: a reputation improving email header

Written by Coen Vermeer on

Several email clients including Gmail and Hotmail offer an unsubcribe feature to their users for commercial mailing lists. This feature adds an extra button to the interface of the email program. To activate this feature as a commercial sender, just add a special header to your emailings: the list-unsubscribe header. As a benefit, using this header will reduce the number of spam complaints and it will improve your deliverability and email reputation.

Email headers

Let's start at the beginning. A 'header' is the technical information that is added to email messages such as sender, subject and time of sending. This information is picked up by the receiving mail server and is processed in the delivery and display of the email. Senders can also add headers to emails themselves in order to give instructions to the receiving system (mail server). This information cannot be seen by the recipient (unless he starts digging into the HTML source code). For example, a DKIM header is added to prove to the receiving mail server that a sender is authentic.

Unsubscribing with a list-unsubscribe header

Which brings us back to the list-unsubscribe header. This is extra information added to an email which contains instructions on how to display an unsubscribe button in the email. When someone uses the button, a message will be sent back to your system enabling you to process this request. Describe how and where you want to receive these messages in the header. Using a CRM package or marketing software? Then this software can receive and automatically process these requests to unsubscribe.

The software will receive a request to unsubscribe from Hotmail when a recipient uses the list-unsubscribe header in this email client. When someone uses this opt-out, a message is sent back to your software for further processing. The list-unsubscribe header supports both unsubscribing by email or by hyperlink.

An example of a list-unsubscribe header:

Subject: More info on List-Unsubscribe
Date: May 10, 2011 11:30:02 AM CDT
List-Unsubscribe: <>, <>

Benefits of a list-unsubscribe header

The most important reason to use these headers is managing your email reputation. A good email reputation guarantees proper delivery of your emails in the inboxes of your relations. Too many clicks on the spam button will have a bad influence on your overall reputation. And your messages will eventually end up in the spam folder of all of your recipients. Some recipients click on the spam button just because they don't want to look for the unsubscribe button or they don't want to go through the entire process of unsubscribing. And thus wrongfully harming your reputation. The list-unsubscribe header makes sure the unsubscribe button is found just as easily as the spam button. In Windows Live it's not even possible to use the spam button when a list-unsubscribe header is added.

An unsubscribe link added by the sender can be mistrusted by recipients every now and then. Giving them the idea 'they are only in it to sell, so they won't process my request'. An unsubscribe link in the interface of the email client will seem more reliable.

Finally, spam filters will be positively affected when they see a list-unsubscribe header in your email. Your emails will pass through to the inbox more easily. The list-unsubscribe header is a kind of guarantee that you are a legitimate sender. It will also simplify the process of monitoring your reputation for the guards of email traffic (Return Path, Lashback, Listbox, and others).

Replacing the unsubscribe link

A list-unsubscribe header cannot yet replace the 'regular' unsubscribe link in commercial email because not all email clients use this feature yet. For example, Microsoft Outlook does not offer this feature yet (!). Dutch legislation requires you to use an unsubscribe function in your emailings. Eventually, list-unsubscribe might become the new standard when it comes to unsubscribing. It can be applied easily and processed automatically. Furthermore, the number of email clients and senders using the feature is still growing. Amongst these email clients are Windows Live Beta, Gmail, Yahoo and Yahoo! Groups, and AOL.

List-unsubscribe is just one of many features that can help you manage your email reputation and isn't the biggest or most important. But it is a tool that can be easily deployed and recipients respond well to. So start using it in your email templates today!