August 2017 - Email Marketing

The Most Important Click for Your Brand

Subscribers of legitimate mailings often fail to unsubscribe when their interests change, and instead mark further mailings from this sender as spam. This negatively influences sender reputation and further mailings from that brand and ESP. How can this situation be improved? Christian Schäfer Lorenz and Sven Krohlas from 1&1 Mail&Media Applications look at an easy-to-implement solution.

Red Newsletter

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Email is a major building block of marketing campaigns. Our intuition tells us that the more receivers are being addressed by a mailing, the higher the outcome for the advertised brand will be. Also senders are interested in sending large quantities of emails, as they are usually being paid by email volume. But do more emails really imply greater marketing success? That impression is about to change.

Users’ interests change over time. As a result, sooner or later users might want to unsubscribe from mailings that they had opted in to before. This can be hard for them to do. Some unsubscribe forms require users to re-enter personal information like their email address, their password or even to solve CAPTCHAs to prevent bot activity. Users often fail to finish that process successfully, as they can't remember which password or email address they used on that site. To resolve this situation, users start flagging – formerly subscribed, now unwanted – messages as spam. User-specific and global spam filters learn from these user decisions and handle the issue from there on.

Marketing emails: Paid by volume, filtered out en masse

The result? Marketing emails, paid by volume, end up in spam folders. Our data shows that about a quarter of emails in the spam folder of users participating in our survey are legitimate mailings. Even worse: Those spam-classified emails have an influence on the reputation of the ESP and brand, resulting in grey- and blacklistings of domains and IPs.

Legitimate emails flagged as spam: A lose-lose situation

No one profits from this situation. Users are unhappy due to the number of messages they perceive to be spam. It is unlikely that a user will go back to a brand they feel they have been spammed by and become a customer again. Other users might not receive the newsletter they are waiting for as the sender's reputation is too low to get mails delivered. Brands do not get the click rate they expect. ESPs get their mail flows rejected or routed into the spam folder and ISPs have to handle support requests from unhappy users and need to cope with more load than necessary on their systems.

Modern email user agents offer many convenience features which usually take just one click to use. Forwarding mails, replying to a list or to the sender only, or marking messages as junk are actions that can be done by just pressing a button in the user interface. So how can unsubscribe be made easier in a similar way to resolve the current situation? For nearly 20 years, the List-Unsubscribe header has been standardized in RFC 2369. It specifies that the command (a mailto-link or URL) in that header should "directly" unsubscribe the user from a list. The way this feature is currently being used clearly indicates that this wording is open to interpretation: In practice, opening the URL often does not unsubscribe the user without further interaction with the opened site.

One-click unsubscribe – the most important click for your brand

To put an end to this confusion, RFC 8058 has been proposed. RFC 8058 defines a standard to signal one-click unsubscribe functionality of a link in a List-Unsubscribe header. Based on those links, easy-to-use solutions to unsubscribe users from mailings they no longer want to receive can be implemented in the mail user agent. It is possible to offer a reliable unsubscribe button to users, to automatically unsubscribe from a mailing. Context sensitive actions are also possible, like offering the user the chance to unsubscribe when moving a message into the spam folder. Such user interface elements will massively reduce the number of spam complaints about legitimate mailings, thus improving reputation and deliverability for bands and ESPs. The standard is also very easy and straight forward to implement, as it only requires an additional header to be added to mail templates and minor adjustments to the unsubscribe scripts that the List-Unsubscribe header refers to.

ISPs, on the other hand, will have to decide when to offer unsubscribe assistance to their users. Requesting a URL in a non-legitimate mailing would signal to a spammer that this account is actively being used, thus motivating the spammer to send even more unwanted messages. So ISPs have to base their decision to show such features to the end user on the trust associated with the sender, expressed by IP or domain reputation or the result of global spam filtering mechanisms.

Email has been a very successful communication protocol since the beginning of the Internet. Nevertheless, the email ecosystem has to deal with new challenges on a regular basis and the protocol stack has to be adjusted accordingly. RFC 8058 will solve the issue of reliably unsubscribing from no longer wanted, legitimate mailings, thus improving the effectiveness of marketing campaigns and user satisfaction, and reducing resource needs. Every email sender should implement this standard as soon as possible.

Christian Schäfer Lorenz
Since 2014 Christian Schäfer-Lorenz is Head of Application Development at 1&1 Mail&Media Applications SE (WEB.DE, GMX, In this role, he directs the mail security team and is responsible for cloud and mail products. In 2015, together with his team, he integrated an easy-to-use end-to-end encryption based on pgp into the gmx and mail services.

Sven Krohlas
Since 2014 Sven Krohlas works for the mail security department at 1&1 Mail & Media Applications SE. His main tasks are malware detection, phishing protection and spam filtering for more than 30 million monthly active customers at WEB.DE, GMX and He is one of the chairs of the eco competence group email and co-chair of the M³AAWG collaboration committee.

Please note: The opinions expressed in Industry Insights published by dotmagazine are the author’s own and do not reflect the view of the publisher, eco – Association of the Internet Industry