How to Avoid Common E-mail Delivery Problems

By Nov 22, 2005

(Direct) Industry experts estimate that more than 20% of all opt-in commercial e-mail is erroneously blocked by spam and content filters. But there are many things you can do to avoid being part of this statistic.

One is to use an e-mail service provider. But that’s not the whole answer, since the relative ease of using an ESP has led to complacency among some e-mail marketers.

Here are four common deliverability problems that can occur even when you’re using a trusted ESP. Keep them in mind before clicking the send button.

Using your ESP’s default tracking links.Many e-mail marketers do this. Link-tracking URLs are great mechanisms for knowing who’s clicking, where they’re going and if they’re converting. But while the stats are essential, using your ESP’s default URL to gather them is not. Why? If any ISP or corporate mail server administrator is blocking any part of the default links from your ESP, your campaigns could get blocked.

There is a very simple solution to this problem. Many ESPs support the ability to define a DNS-based domain alias. For example, if your domain name is xyzcorp.com, you might set up web.xyzcorp.com to point to your ESP’s link-tracking server. When you do this, links with web.xyzcorp.com will appear instead of the ESP’s default links.

Using your ESP’s default image tags. While leveraging an ESP’s document or image library is a great way to offload image-hosting resources from your own Web server, it can lead to deliverability problems. In short, your mail may be blocked if you make any reference to your ESP’s default server locations, including those linking to its document or image libraries. Use of a DNS-based domain alias in image tag references will allow your campaigns to take on a unique identity—and not be tainted by the negative actions of other customers your ESP may be hosting.

Before closing the book on this subject, it’s essential that you look at one of the most important tags in your campaign: The one that tracks your HTML opens. If this tag sports your ESP’s default server location and not your domain name, you’ve got a problem. You’ll want to work with the ESP to get your URL embedded into that tag so it won’t get blocked by a spam or content filter by mistake.

Relying on your ESP’s white-list status while racking up abuse complaints. The e-mail community has worked hard over the past few years to foster positive relationships with ISPs and corporate mail server administrators, and this has culminated in the creation of white lists—a list of accepted items in a particular set. How do they work?

An ESP’s IP address space is placed on these lists and e-mail sent from these ESPs passes through unfiltered and untouched by spam filters.

But this is only half the story. What most marketers don’t know is that, based on user complaints, white-list status can be revoked at any time at an ISP’s sole discretion. The same large ISPs that maintain white-list programs also employ global abuse registries that track the number of gripes stemming from a certain mailer. Once the threshold is reached, white-list status is terminated and blocking will begin. Complaint thresholds vary from ISP to ISP and often are moving targets.

Want to stay on white lists? The only way is to maintain a low complaint level. Most ESPs will allow you to see the number of complaints generated at AOL and United Online (a multibrand provider of consumer Internet subscription services) so you can tell if you have a problem.

The safest bet is to keep your complaints below one in 1,000 messages sent. If you go above this level you likely have a permissions problem. Review your acquisition strategy and make sure your opt-ins understand clearly what they’re signing up to receive. And consider using confirmed opt-in—it will result in an overall lower list size but will increase your list performance in the long run. User complaints will be lower and you will get more mail delivered.

Not using a dedicated IP address. Most informed marketers who use an ESP make sure their campaigns are being deployed from a unique IP address. This can improve deliverability for some business-to-consumer marketers with lists that include more than 100,000 recipients and have high concentrations of AOL addresses.

But beware: AOL has a very strict user complaint policy, and it could block parts of your campaign if recipients falsely report your e-mail as spam. And you’re particularly vulnerable when all your mail to AOL is routed through a single IP; all of your user complaints are then pegged on that IP.

The answer? Employ an address pool of, say, three unique IPs, and you’ll essentially spread your complaints per IP across three servers and thus increase the chance that all your mail will be delivered successfully at AOL.

One benefit of using an ESP is to leverage its arsenal of reporting tools. This starts with the old standards of measuring opens, reads and clicks. But you should take it a step further by reporting on your list performance by ISP. This will give you an at-a-glance view across all their files. Granted, this is a reactive strategy, but it will let you flag problematic ISPs or domains because their data will have lower performance compared with that of other ISPs. And if you do spot an ISP with dramatically lower performance data (but not zero), there’s a good chance your campaigns will be flagged as spam and redirected to the junk or bulk mail folder. This usually indicates a content problem. You might be using words in your campaign to trigger a content filter or your HTML could be malformed.

If you find an ISP where your performance data is coming back all zeros, you’re likely blocked from that ISP. Often this is caused by abuse issues stemming from user complaints. Your ESP will be more than happy to help refine your acquisition strategy and consult with you on how to limit user complaints. Beyond that, it should be able to mediate the situation with the ISP and restore your mailing status.

The future? The hope may be in global e-mail reputation databases which will be built around e-mail authentication technologies. ISPs and corporate mail servers will decide whether or not to put a message through a traditional content filter based on the sender’s reputation.

The day is coming when e-mail campaigns from reputable senders will be sent directly to inboxes unfiltered and untouched by traditional spam or content filters. But that’s still a long way off. Until then, smart e-mail marketers should remain alert to the changing landscape to achieve maximum deliverability.

Ross Kramer (rkramer@listrak.com) is president of e-mail marketing software maker Listrak in Lititz, PA.