Dynamic E-Mail Messaging Demystified, Part 1

A little over a year ago, I wrote a survival guide to dynamic messaging. Since then, the subject has only grown in profile and, if my experience is anything to go by, confusion for many marketers. In the next few columns, I’ll look in more detail at what is meant by “dynamic messaging”; what its costs; what the benefits, pitfalls, and advantages are; and where and how to utilize it effectively.

Before we can plan a dynamic message, we must understand the techniques needed to create such a message. Delivering a dynamic message requires an email platform capable of customization. When it comes to email customization, the devil is in the details. Similar-sounding techniques may have unexpected limitations.

There are four basic customization mechanisms.


Divide the list into segments and send each segment a different message. Nothing hugely groundbreaking here; we’ve been doing it in direct mail forever. However, this simple form of customization shouldn’t be underestimated. The concept is simple, but the effect is powerful.

The problem with segmentation is it can only go so far. Cost and complexity increase geometrically with the number of segments. Segmentation alone, therefore, cannot be used for true one-to-one messaging.

Variable Substitution

Fields are placed in the message template representing recipient attributes and are substituted for each recipient. This can be used for anything from personalized salutations (Dear ,) to details of specific purchases or interactions. This capability, in the form of ink-jetting, has been available in the print world for over a decade.

It’s important to realize in email, this technique is used whenever tracking of open and CTRs (define) are employed. Tracking is achieved by customizing links so they’re unique to each recipient.

Though variable substitution has great value, it only allows fairly simple levels of personalization. All too often, it’s used for no more than cheesy “Dear John” greetings.

Conditional Blocks

A piece of programming code is placed in the message to perform an if-then test. This allows recipient attributes to be used to include or exclude specific content. For example, a special offer may be included only for customers whose product license expires in less than 30 days.

This type of customization could be achieved by treating such customers as a separate segment. However, each conditional block doubles the number of segments. This rapidly becomes unmanageable.

Conditional blocks allow truly variable content. Unfortunately, they also make the message templates much more complex, so, like segmentation, they don’t scale well. They also involve inserting programming code in the message template, so are prone to unexpected coding errors.

Content Insertion

This is very similar to variable substitution, with a twist. As with variable substitution, a field is placed in the template that is later substituted. Unlike variable substitution, entire sections of content (phrases, paragraphs, etc.) are inserted based on recipient profile. This inserted content may itself contain substitution fields.

This difference means it’s necessary for the customization engine not only to insert the content but then to perform variable substitution within the inserted content: customization within customization! This is necessary not only to perform personalization within a dynamic section but also to track CTRs within inserted content, which is an essential capability. For example, a message might contain one of 15 different opening paragraphs based on purchase history, with each paragraph referencing specific past purchases and linking to a different location.

With this technique, there’s no limit to the effective number of individual messages that can be created. Yet content insertion has two problems. First, it adds a significant additional complexity from a technical perspective. Not all email systems are capable of the customization-within-customization that’s required. Second, it separates the content from the message template. Though this may not sound significant, it has enormous impact on the production process. Content must be created, proofread, and approved out of context, something people often find very difficult.

These customization techniques can be used individually or in concert, providing a wide range of capabilities and options. It’s common to see conditional blocks and variable substitution used together. For example, you insert a special offer for customers whose product license expires in less than 30 days and indicate for each customer exactly when that is. Fully dynamic campaigns using content insertion may also use segmentation. Though not technically necessary, doing so often simplifies the analysis and reporting.

If your goal is to run truly dynamic messaging, your email platform must support all the above customization techniques. If it doesn’t, check with your vendor.

Until next time,


Want more email marketing information? ClickZ E-Mail Reference is an archive of all our email columns, organized by topic.

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