EMAILS, EMAILS, EMAILS they are everything. They can drive up your sales and business but it needs to be done correctly. Getting them leads to interact with you and convert them is key.

As email marketers, we strive to produce great content and work to build emails that drive brand awareness and engage our customers to entice them to interact with us. Emails that generate positive interaction and engagement can boost your Sender Score and Deliverability Reputation. Your email sender reputation is a major factor in determining whether or not the email you send is going to actually reach a user’s inbox.

Ensuring you have a good email sender reputation involves a multitude of factors, including the following IP warming rules, having a clean email list, and making sure you’re in compliance with legal regulations. The dark art of Email sending reputation is comprised of multiple complex calculations which are used to determine trust and credibility of the email sender. In a nut-shell, Deliverability Reputations are based on 3 core principles:

Interested in emails? have a look at our instalment on metrics ‘email marketing metrics’

  • IP Reputation: Indicates how much users want to get email from an IP address by measuring the responses of bounces, spam traps or unwanted bulk mail (UBE)
  • Content Reputation: works on a set of criteria that determine the sender’s quality by their email campaign content. Content which is unique, relevant and engaging to subscribers stand the best chance of reaching the customer.
  • Domain Reputation: Things like domain age, how the domain identifies across the web, and whether it identifies in the entertainment, advertising, finance, or education industries can all impact your domain reputation.

IP and Content Reputation can easily be fixed and improved by adopting some best practices of sending. However, Domain Reputation is often the most difficult to decide and build as it involves key decisions in defining the reputation of a brand identity. Deciding on a domain name to use for sending your marketing emails is often the first hurdle businesses face when deploying their Marketing Automation platform. This sending domain is most visible and evident to your subscribers when (if) your email arrives in their inbox.  

Though an immediate temptation might be to use your corporate domain Top Level Domain (TLD)  e.g., it’s an industry best practice never to send marketing communications using corporate domains. Any reputation damage caused by spamming will seriously impact the deliverability of your corporate (non-marketing and business critical) emails.

The industry recommendation is to use a subdomain of your parent domain e.g.; or to alternatively register a separate Top Level Domain (TLD) specifically for sales and marketing communications e.g. or

By using this approach, you mitigate the risk of reputational damage to your corporate domain. The domain and subdomains that you send from are one of the factors that impact your reputation, and just like in real life, a parent (domain) has a separate reputation from its (subdomain) children.

Using subdomains to send all mass communication can help to mitigate the negative consequences of situations where your company finds itself blacklisted by ISPs.

By establishing separate sending sub-domains for commercial Vs transactional you will also get a better insight into the different results that you’re seeing in your reputation monitor, as it will simplify the process of identifying which emails are struggling and why.

For example:

  • Transactional Domain  :
  • Commercial Domain:

Ultimately, ISPs decide through their own datasets whether you send good emails or not. For B2B senders, many corporate businesses will operate strict inbox filtering tools for their employee’s email accounts.

A key challenge many B2B email senders face is a natural turnover of bouncing email addresses as corporate email addresses are closed when an employee (your subscriber) leaves the business.

So while Reputation Scores might be a good indication of email sending practices, fixing it from low to high does not automatically guarantee that all email campaigns will land in the inbox. The best way to fix email sending is to look at the source and focus on deliverability (the rate at which a sender’s email campaigns land into the inbox, as opposed to the spam folder). Focus on communicating with your most engaged customers and accept that old/non-engaged customers should be deleted.

Much like your website URL, branding is important. Maintaining brand-recognition between your email sending domain and your corporate brand is important and your email sending domain should work together with your website domain name to create a cohesive brand so your subscriber can recognise and trust your brand as a reputable email sender.

It goes without saying that you should avoid domain branding which appears to the end user as spam-like or untrustworthy. Avoid any keywords which would appear to have negative connotations to a recipient.



Contrary to popular sentiment, the internet does not need to end with .com. As the Web expanded, new Top Level Domains (TLDs) have become more common and accepted, especially by users who have grown up with the web. With the introduction of Generic top-level domains (gTLDs) a common question has arisen as to whether the sending reputation of these gTLDs would differ from the sending reputation from the traditional Top-Level-Domains (TLDs)  e.g. .com, .net or other country-code top-level domains (ccTLDs) e.g.,

The .email domain is a generic top-level domain (gTLD) that has become an attractive alternative for email marketing purposes. The .email gTLD is a new namespace suitable for the communications industry and is perfect for email platforms, inbox zero guides and training tools.

A .email domain extension can be registered worldwide without any restrictions, and is a memorable naming alternative to .com, .net and the country-code top-level domains (ccTLDs).

Experts predict gTLDs will become as common as traditional domain endings. Many prominent businesses have adopted or switched to new TLDs, giving them more legitimacy for others to do the same. The only flip side of this is that there will always be people who are unfamiliar with the new endings.

There is a common misconception that .com has the best chance of topping search engine rankings and email deliverability. The fact is, every TLD can rank in the top positions if SEO and deliverability, provided best practices are conducted. Though .com is the most popular extension, it’s for that reason it’s frequently ranked in top positions.

It’s worth noting that in the eyes of Google and other search engines, all TLDs are equal. New gTLDs and ccTLDS won’t carry any inherent SEO value, but neither will they be seen as inferior to .com.

It’s generally accepted that if your email has quality content and your IP Sending Reputation and Sender Score are good, then there are no reasons why a sending domain would be penalised. Unfortunately, there is little open-information and documented analytics on the performance of using gTLDs to compare.

We’ve found through speaking our client’s who have used .email domains for their marketing communications, that although they were sceptical and cautious at first, after following best practice IP Warming and Subscriber List Management, they identified no negative implications for using such generic top-level domains.

Provided you have properly configured the domain’s Sender Policy Framework (SPF) and DomainKeys Identified Email (DKIM), and have adequately maintained a clean subscriber list and performed optimal IP Warming, the building of brand and customer reputation and their familiarity to your email address is driven hugely by the content you send.

The most common Spam Filtering Software is SpamAssassin which is very widely used to filter mail, both in its open source version and buried anonymously deep inside countless commercial spam filters and filtering appliances. Many ISPs offering Email Inboxes will use SpamAssassin to do pre-mailing content checks or looking at why content-based filters are objecting to a particular email in their systems. It’s very widely deployed, and influential far beyond the size of it’s deployed base. Another commonly used alternative within the corporate enterprises is MimeCast which operates very similarly to SpamAssassin. For the purposes of our investigation, we have assessed SpamAssassin.

SpamAssassin is a score-based spam filter – it checks an email against hundreds of rules, adds up the scores of each rule that matches and, in typical setups, decides the mail is spam if the total score is five or more. Here are a few of the rules and scores (from the 2006 version of SpamAssassin)

  • 1.392 Advance Fee Fraud (Nigerian 419)
  • 0.493 Refers to an erectile drug
  • 1.995 Subject contains G a p p y T e x t
  • 0.496 Message is 40-50% HTML
  • 2.100 From: domain has a series of 7 consonants
  • 1.635 Possible porn – Hardcore Porn
  • 2.013 Contains a URL in the BIZ top level domain
  • 1.273 Contains a URL in the INFO top level domain

With the SPAMHAUS Top 10 of “bad” TLDs (June 2019) indicating common “bad” domains based on the number of Bad Domains Detections Vs the Number of Active Domains Observed, it’s wise to avoid using common ‘spammy’ gTLDs in your branding.

RankDomain% Observed Vs BadBadness Index

Back in 2004, The SpamHaus Project pushed ICANN to create a new trusted-sender system using a .mail top-level domain. SpamHaus proposed that such TLD would provide a way for email recipients to ensure that incoming mail is sent by organisations were reputable, and that the registered party agrees to abide by certain anti-spam mailing practices. Though their intentions were honorable, as expected, the proposal proved controversial and from a technical perspective proved troublesome as the .mail domain was considered so central to private networks’ internal functioning that they can’t be allowed onto the public internet.

This solidifies why .email has become a very appealing gTLD for email marketing as it’s clearly evident what it’s intended use is for, and what the sender intentions are.

The .email domain is low on the SpamHaus index, perhaps indicating that the registry is doing a good job of enforcing policies and shunning abusers.

RankDomain% Observed Vs BadBadness Index

Before you settle on a domain to register, take a moment to check if the TLD you’re deciding on appears on any email block lists. If there’s anything to suggest the gTLD is viewed with contempt online, that could be a bad sign. We recommend avoiding such a TLD because it will make your website look like it could be spam, which isn’t a good thing.

The only arena we truly see being impacted by the influx of new gTLDs is email (signup) validation. Depending on the depth of current email validation setups, the impact will vary. B2B email senders might find tighter controls by the subscriber’s corporate spam filters.  

For owners of .email domains, should you choose to subscribe to 3rd party sites/subscriptions with a .email address, then you might find that some web form validations may reject gTLDs as a valid email as they are using outdated regex scripts or a hard-coded list of acceptable TLDs. Likewise, you should also consider your own web-form and CRM email validations practices, as its highly likely that your customers will soon register their own gTLD domain.