How to Improve Your Email Deliverability Rates

Written by Mitchell Harper, Interspire Co-founder
Published on 23rd May 2007
 

Introduction

Last week Eddie and Rodney were attempting to send an email to a Hotmail account we've setup to make sure our emails get to the intended recipients without any problems.

Our mail server was reporting that the emails were being delivered, however we couldn't see them in our Hotmail account. The emails weren't bouncing back and they weren't appearing in the junk mail folder. Puzzling to say the least.

If you've ever been in a situation like this with one of the big email providers including Hotmail, GMail, Yahoo and AOL then you know it's frustrating and confusing to those of us who send emails regularly.

We have over 95,000 people on our mailing list and after a quick look at the list I noticed a large majority of our subscribers use one of the big email providers mentioned above. If our newsletter failed to get into the inbox of all of these people we'd probably only reach 10,000 - 20,000 subscribers (between 10% and 20% of our total subscribers); hardly what we want.

Getting Your Email There on Time

What would be some of the reasons why your email might not reach the intended recipient? The first problem are you subscribers, believe it or not.

How many times have you personally signed up for a mailing list (even using double opt-in) and then clicked the "Mark as Spam" button in your email client because you couldn't remember when you in-fact did sign up? I know I've done this on many occasions.

This hurts companies who send legitimate emails, because if enough recipients mark their emails as spam, the big email providers take notice and ban their mail server. This process is called black listing and once your mail server's black listed it's extremely difficult to get off the list. More on that later.

Next up there's the spam algorithms and other checks that mail servers employ. AOL for example used to implement a technique called rate limiting whereby they would only accept a certain amount of emails from a mail server at a time - send more than you're allowed to and you're considered a spammer and were black listed.

All of the big email providers have their own proprietary algorithms for checking and deal with email spam. The good news is that a lot of the things the algorithms check for are easy to avoid.

Take a look an article Eddie wrote called "Avoiding the Spam Filters and Other Email Marketing Tips". Follow the steps he talks about in the article and you'll improve the chance of your email getting through significantly.

More Ways to Avoid the Spam Filters

After doing some research using our good friend Google, we've put together a list of things you can do to reduce the chance of your email being marked as spam and/or never reaching the intended recipient in the first place:

• Make sure your list only contains double opt-in subscribers. Sure your list won't be as big as it would if you didn't require opt-in confirmation, but it will be safer, more valid and subscribers will be less likely to flag your emails as spam or complain to their email provider.
   
• Using the link to Eddie's article above, do your absolute best to make sure your email doesn't look like spam. The spam filters are smart, and for everything it finds in your email that looks like spam it gives you one point. When you get to a certain number of points your email is rejected, so the less spam points the better.
   
• Check to see if your mail server has already been blacklisted. You want to check your ISP's mail server or the mail server of your web host. To see the IP address of the server sending your emails just send an email through your mail server to yourself and view the headers of the email in your email client.
  
  The last received line in the headers will contain the IP address of your ISP or web hosts mail server through which your email was sent. For example, you might see 3 received lines in the header, like this:
  
  Received: mail.somehost.com
  Received: 220.403.8.65
  Received: 201.56.88.31
  
  In the example above the IP address of your mail server would be 201.56.88.31
  
  Once you've found your mail server's IP address read this helpful article. It lists the different sites you can check to see if your mail server has been blacklisted.
   
• Check with the postmaster services of the big email companies to see why they are rejecting your emails. If you don't know what a postmaster is, here's Google's definition:
  
  A special type of user responsible for tracking failed mail delivery. A post-master is responsible for following up on queries from users and other postmasters. Internet standards require that the postmaster account be valid at every domain.
  
  AOL's postmaster is http://postmaster.aol.com/ and Hotmail's is http://postmaster.hotmail.com/. You can find postmaster details for other email services with a quick search on Google.
  
  One thing to remember about postmaster services is that they make it difficult to get your email through. The theory is that the harder they make it, the less effort spammers will give, thus stopping the majority of them from trying.
   
• You may also want to use one of the email accreditation services available, such as SPF (sender policy framework) records for your mailer or DomainKeys. You can also look at services such as SuretyMail to help improve the deliverability of your emails, particularly if you're trying to send millions of emails per month.
  
  I won't go into too much detail, but SPF is a way to identify and reject forged addresses in the return path of an email, which is a common technique spammers use to send email. DomainKeys is an email authentication system that was developed at Yahoo. It was designed to verify the name server being used by someone sending bulk email.
   
• Finally, you should educate your subscribers. Immediately after they join your mailing list you should give them a series of steps to white list your email address. White listing is a way of telling their email client to allow all emails from you into their inbox.
  
  Each big email provider has different ways of allowing subscribers to white list email addresses, the most common being to add them to their address book or contacts. For more on white listing see this article on Wikipedia.

Read More Articles Online

To read dozens more articles like this one, just visit Interspire.com/Content

Interspire News

• WebEdit NX Beta Video + Testers
• 10 New CSS Templates for SiteCenter NX
• Have you seen our 3 educational email courses?
• Behold! The great wall of Interspire testimonials (video)