Successfully Navigate E-Mail Append

As businesses prepare their 2006 marketing budgets, many lament the number of contacts in their databases without email addresses. In recent years, many traditional database houses that offer list hygiene services have added email append offerings. One might expect the process to be straightforward and effective. Unfortunately, email append is still fraught with dangers. Choosing the right vendor is critical to a successful outcome.

The core of the problem, as is so often the case with email marketing, is permission. Smart marketers understand the importance of permission and only accept explicit opt-in. Obtaining that permission presents some difficulties.

Compared to a traditional offline data append, email append contains an additional step: permission request. The process is typically:

  1. You provide a list of customers to the vendor, which matches names and addresses against its database.
  2. The vendor sends an email to matched addresses asking for permission to provide you with those addresses.
  3. The vendor returns your list with email addresses added for those customers who agreed to receive email from you.

To obtain a useful match rate, the vendor must have a large database to compare your list against. In an ideal world, this database would consist entirely of recent confirmed opt-in (COI) subscribers who agreed to receive third-party solicitations. Unfortunately, such databases are about as scarce as hen’s teeth. So vendors have to cut some corners and work with the available databases. The issue is which corners have been cut, and how deeply.

Although the vendor will typically send the permission request from its own systems, the request will still have your company name in it. If the vendor’s list management practices are poor, you risk being found guilty by association and labeled a spammer for using the vendor.

It’s essential to know what to ask when evaluating a potential vendor.


Most email append databases are compiled from multiple sources of varying quality. As the saying goes, “Garbage in, garbage out.” A database is only as good as its worst source.

Where does the vendor obtain its addresses? What checks are in place to ensure collected addresses are valid? Does it accept confirmed opt-in, opt-in, or opt-out lists?


Not all permissions are created equal. Many vendors maintain a record of address sources. Ideally, they also keep a detailed record of subscription and activity history. Such a history is needed to disprove spam allegations.

Does the vendor perform its own opt-in confirmations on purchased addresses or rely solely on the original opt-in? Does it have details of what each address opted in for? Does it keep evidence of that opt-in (location, date and time, source address)? Can it trace every address back to its source?


Old addresses are subject to bounce, complaint, and spam trap issues. With high email churn rates and increasing sensitivity to subscriber privacy, obtaining and maintaining an append database can be extremely difficult.

What are the maximum and average ages of the addresses in the database? What history does the vendor retain concerning communications with each address? How and when are bouncing addresses removed? Are nonresponsive addresses removed, and what are the removal criteria?


Since your vendor will send email on your behalf, you should do much of the same background investigation you would with an email service provider.

What domains does it send from? What IP addresses? Where is it whitelisted? Which feedback loops is it on? Is it blacklisted?


Many vendors prefer to send an opt-out confirmation rather than an opt-in permission request. For years, ISPs have instructed their customers not to opt out of messages they didn’t request. The double negative of not opting out of something you didn’t request doesn’t constitute a positive declaration of consent.

Will the vendor send an opt-in request or only opt-out? Does it charge based on matches, deliveries, or permission responses? What are its typical match, delivery, and opt-in rates? What percentage of its clients use opt-in over opt-out?

Used judiciously, email append can be an effective tool to rapidly add email addresses to your customer database. However, it is expensive and can be risky. Whether you use it and which vendor you choose should depend on how sensitive you and your customers are to permission and privacy issues, and how much risk you’re prepared to take.

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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