Barry Clifford

Email Deliverability: Making it into the inbox.

According to a recent study, less than 75% of commercial B2B emails actually make it in to the targeted inboxes[1]. If this seems surprising to you, take a look in the spam folder that your email client most likely provides – you’ll probably see lots of fairly legitimate business offerings mixed in there with the Viagra offers and Nigerian bank deals.

In actuality, your email client’s spam filter is the last hurdle in a number of systemic attempts to weed out annoying and illegal emails. Email deliverability is a science, so what follows is not a complete itemization of all that’s out there, but rather a brief glimpse at some of the things that can stop your email from arriving.  If success in your business model is tied to your email campaign, then knowing some of this can have a direct impact on your bottom line.

In the category of things over which we have little direct control, is filtering at the ISP level. Spam has become not only an annoyance to users, but a true hindrance on the infrastructure of mail delivery, with more that 80% of all email traffic being considered spam[2]. Imagine driving on jammed highways where more that 80% of the cars were going nowhere? So to keep their customers happy, ISPs have developed ways to cut down on the capricious, unwanted burden spam places on its servers. Enter black lists.

Black lists are databases of IP addresses and domains that have a reputation as being the originators of spam. These lists are used by many ISPs to confirm that email senders are legitimate and to limit unwanted email traffic. Factors that might result in blacklisting are:

  • Hard Bounces – Undeliverable email because of old or nonexistent email addresses. If your mailing results in a certain percentage of hard bounces, you might be tagged as a spammer;
  • Spam Traps – emails sent to specific addresses that the blacklist keeper maintains for the purpose of catching spammers. This is why purchasing mailing lists online can be a dicey business;
  • User complaints – reports from email recipients that a piece of mail is unwanted;
  • Volume filters – Literally the sheer volume of email you send can flag you for review by ISPs.

There are other factors that ISPs use in determining whether an email will be delivered, which are more technical in nature.  These include server configurations, SPF and sender ID records, and DKIM and domain keys. Most of these issues are moot if you’re using some kind of third party mailing service.

Also in the no-control category are behavioral factors that are collected by interactive inboxes like Google’s priority inbox that automatically filter email from inboxes based on user’s previous behaviors, including deletes, opens and replies. These go a step farther than user-defined filters, in that they attempt to anticipate what readers will see as relevant. Hopefully, we have crafted our emails and content in such a way to help us score high in the “opened” department.

Things over which we have direct control are our behavior as commercial enterprises, and our content. These are items that will prevent email clients from identifying our communications as spam, and hopefully limit the number of complaints we receive.

  1. Don’t be a spammer. There are specific rules defining what is and isn’t considered spam.  Be aware of these, and at the very least, make sure your communications comply to CAN-SPAM.
  2. Use good mailing lists. These are opt-in mailing lists that you’ve collected, or other opt-in lists that you’ve rented from a legitimate source.
  3. Content. Keep it relevant. You want people to open your emails and react to the offers inside. Users these days are just as likely to use the “report spam” button as a way of deleting unwanted messages from their inbox – regardless of the fact that they may have requested your information in the past. By making sure you deliver what readers asked for you’ll mitigate the risk of being reported as a spammer.
  4. Segment your mailing list. Make sure the message you’re sending is one that the recipient is interested in receiving.
  5. Avoid hyperbolic marketing statements, or stylistic expressions of excitement. Yelling “FREE” over and over, using multiple exclamation points, and placing whole sentences in bold type look cheesy, and probably will guarantee that your email is not seen. Avoid these behaviors at all cost.
  6. Respect users requests. Make it easy for them to opt-out of your email lists and once they do, don’t email them any more. Ever.

In the numbers game of online marketing, getting your message to as many people as possible can have a direct impact on your bottom line. Knowing every detail about what keeps you out of some ones inbox therefore can mean the difference between a bonus or a pink slip at the end of the quarter. If you’re interested in digging deeper, a Google search on “email deliverability” will deliver a host of knowledgeable resources on the subject.


[1] Return Path (2010)

[2] e-Dialog “Manifesto for E-mail Marketers: Consumers Demand Relevance” (2010)