Email marketing is a simple and efficient way of communicating with a multitude of recipients. However, the sending of emails does not automatically mean they also arrive. Before an email appears in the inbox of a recipient, it must negotiate certain hurdles. Particularly, the increased measures to protect from spam, often filter out desired emails – a problem for serious email marketing. However, the solution of this issue is not alchemy. Marketers can improve the email delivery if they know the tasks and pay attention to the technical rules.
Spam emails are not only a nuisance for email recipients, but also for email marketers, who focus on legitimate, commercial emails. A proportion of over 90% spam in the total of email traffic, forces email providers and recipients into comprehensive counter-measures. However, these measures can often affect the deliverability of desired emails.
After the dispatch by the mailserver of the email marketer or his service provider, an email passes through a number of stations before being displayed in the inbox of the recipient. The first stage starts at the provider, where the recipient has his email account. This filters incoming emails according to different methods before delivering them to the recipient. But even when an email has passed the security of the provider, there is no guarantee it will appear in the inbox of the recipient. On the side of the recipient, different filter measures can be employed, as well.

Measures by Receiving Email Providers

The most important measure to prevent the rejection of the sent email by mistake, is to secure the reception by the receiving email provider. This analyses whether the sender is serious and the email therefore desired. Email marketing users have to care for their image, or use a service provider, who takes care of this.
The reputation can have different characteristics. A negative reputation can be caused by a sender, who frequently sends emails, which are classified as spam by recipients or which can technically be identified as non desirable. This may be, for example, because they are not deliverable as a large volume or because check addresses of anti-spam services are targeted.
The result is often an entry in a blacklist. A blacklist contains IP addresses/domains of mailservers, which have been declared as senders of spam.
As a first check, many providers run a synchronisation process of the used IP address/domain with the blacklist. If the IP address/domain can be found on a blacklist, the email will immediately be sorted out or rejected.  Not all providers use all of the many available blacklists. Email marketers should therefore check, whether the providers of their recipients filter according to blacklists and which of these they use. Above all, you need to monitor, whether your own IP or domain data appear on a blacklist (blacklist monitoring). Is this case, an exclusion from the blacklist may be possible. This might come at a charge, however, and must be justified by a good reason.
Even when the IPs/domains of the mailserver are not on a blacklist (neutral reputation), this is still not a guarantee for smooth delivery. After the successful blacklist check you need to take on further hurdles – depending on the provider – greylisting, throttling and spam filters.
The first stage is greylisting. This results in a temporary rejection of an email. Many spam bots (programs, which automatically search for email recipients and target them with spam) do only make one delivery attempt, while serious service providers often make a second attempt, in case the first delivery failed. Greylisting blocks the first delivery attempt and allows a second attempt to pass. This leads to a delay in the sending, as usually a buffer time between the first and the second attempt needs to be bridged. Greylisting does not necessarily have an adverse effect. It is primarily problematic for those in charge of email marketing, who rely on a prompt delivery of their emails.
The second stage is throttling. Many email providers set a maximum number of emails per sender in a fixed time period. When this limit is exceeded, the sending will be throttled, emails will be blocked or end up in spam folders of the recipients. This is based on the assumption that recipients wish to receive rather fewer than many emails. Email marketers should inform themselves with providers, which maximum limits are set and compare theses limits with the number of emails to be sent. Throttling can prove problematic especially in bulk mailing.
The last stage is the spam filter. The spam filter analyses emails according to content-related aspects. Keywords, which indicate spam, can be detected and the emails in question will be sorted out or dealt with otherwise.To reduce the risk of an email being filtered out by a spam filter, you should avoid certain keywords, such as “sex” or “Viagra”.
Once the protective measures of the provider are passed, there can be further hurdles with the recipient. Different email web services, as well as email clients offer their users functions to install additional filters or identify emails as spam. Furthermore, there are measures via plug-ins or external software (e.g. anti-virus programs). It is a bonus, if you know your recipients quite well, in order to be aware which functions they (may) use. Complaints should also be taken into account or the complaint behaviours monitored.
In addition to the filtering of spam by the recipient according to proven concepts, such as the keyword analysis, social filtering is gaining more and more relevance. Social filtering means the relationship between recipient and senders as a social network. The previous communication between a recipient and a sender will be analysed, e.g. the open rate of previous emails, and from this, the intensity of the relationship between both can be established or a social reputation of the sender can be created. This reputation then affects the treatment of the emails from the sender. Key to a high activity and therefore an intensive relationship is the attractive, individual design of mailings.
A general possibility to reduce the type and scope of filter measures, is to improve your own reputation (positive reputation) through whitelisting. Whitelists are positive lists, which accredit a listed sender with a special reputation and secure his emails priviledged status by the email provider.
Whitelisting programs are offered by commercial providers, interest groups and partially the service providers themselves. Email service providers register with a whitelisting provider and will be added to the list once they have been checked. They need to fulfil a number of criteria depending on the provider, in order to prove professionalism. The list will be made available to email providers. As soon as an email is received on the mailserver of the provider, the IP/domain will be synchronised with the whitelists. If the sender’s mailserver can be found on a list, his emails will receive priority. This means, that emails do not need to pass greylisting and throttling, anymore. As a result, spam filters will also apply lower thresholds or may no longer be necessary.
Another benefit of whitelisting is the improved display of emails, as many email providers limit the display of images, links and rich media content. For whitelisting participants, less restrictions may apply here.
In addition to simple positive lists, which list the IP addresses of registered sender mailservers in the same way as blacklists, more comprehensive reputation services are also available. These services collect detailed information on the participants and continually analyse their reputation. The reputation depends on different factors, among them the proportion of non-delivered emails or the security of the mailserver. Email marketers should bear in mind that even with these services, a reputation can turn negative when you violate the guidelines.
As an additional extra, some whitelisting providers offer premium services. Premium providers conclude agreements with email providers and have delivery for their customers guaranteed. Some providers even identify premium emails with special symbols, which promise authenticity and quality to recipients.

Checklist to Improve Your Reputation

In order to improve your own reputation and fulfil the criteria of the whitelisting providers, you should pay attention to the following checklist:

  • The choice of necessary and helpful measures for efficient email sending should be based on your target group and send volume. We recommend a comprehensive analysis of the mentioned factors prior to taking measures. Extensive B2C mailing lists with many freemail addresses will be more demanding than small B2B lists.
  • Opt-outs of recipients must immediately result in a deletion from the subscriber list. If recipients receive undesired emails despite unsubscription and report these as spam, this will significantly damage the sender’s reputation – and not to mention the legal consequences.
  • Obsolete addressed and outdated addresses, which regularly produce bounces, should be deleted from the list. Firstly, because delivery failures have an effect on the reputation and secondly, because obsolete addresses are often reactivated as spam traps after a dead phase.
  • If you wish to access more than one address database, you should synchronise these regularly in order to take into account all delivery failures and unsubscriptions.
  • You should set up complaint feedback loops (FBL) to receive prompt feedback and response quickly to issues, such as bad delivery quotes, increased spam frequency, technical misconfiguration or recipient complaints. FBLs are direct, formalised channels between senders, providers and recipients. The delivery of feedback takes place per email to the sender.
  • Reverse DNS entries should be set up correctly. Reverse DNS identifies the corresponding domain name for an IP address. The established affiliation of reverse DNS and normal DNS enquiry should be consistent.
  • The email server behind the sender domain should also be able to accept and process emails.
  • The domain should be configured for Sender Policy Frameworks (SPF). Via SPF, you can determine, which hosts can send emails via a domain. This prevents non authorised hosts from misusing a domain name for the sending of spam. This is an important function for email marketers, who carry out their sending via servers of an external provider.
  • The domain should be configured for Domain Keys Identified Mail (DKIM). The email header can include digital signatures, which authenticate the sender. Here, the receiving mailserver verifies the signature my means of a public key, which is deposited on the DNS server.
  • A complete, up-to-date entry should be available. A WHOIS entry contains information on the owner of a domain/IP address. It should also be consistent, i.e. the same for a normal and for the reverse enquiry.
  • Dynamic IP addresses should be avoided as they can often be found on blacklists.
  • You should continually monitor your own reputation. Even when senders are sure, that they have not violated the rules, they should regularly check, whether the IP addresses of their servers are on a blacklist. Newly rented addresses should immediately be checked.

The reputation of a sender is often the key to improving deliverability. Companies can either fall back on specialised service providers, who translate the measures for securing delivery or try to build up a send reputation for themselves. As a leading German provider for email and RSS marketing, software provider artegic AG will support you in both ways. For ELAINE FIVE customers, artegic offers one of the largest German SaaS delivery networks. The consistent permission marketing of artegic customers, the direct contact with providers, as well as the certification and membership in international whitelists guarantee a maximal reputation and delivery reliability.

More information on whitelisting and other digital marketing topics

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