E-Mail Response Addresses: Static or Dynamic?

E-mail is a two-way medium. If you use email to deliver marketing campaigns, inevitably you’ll receive responses, even if you tell recipients the reply address isn’t monitored. These responses can be a valuable source of information if they’re processed in an efficient and timely manner.

Whether you use static or dynamic response addresses significantly affects your ability to process these responses. The decision of which to use has never before been so difficult, or so important.

Using a Static Address

The traditional approach is to use a single, consistent response address. However, static addressing has two main problems. First, the reply address may not be the same as the sending address. This can be the case for a number of reasons, including mail forwarding, address aliasing, or even role addresses. It’s often impossible to determine which list member is responding.

Worse, some systems send bounces from the postmaster address with the original recipient’s address rewritten as an unintelligible internal address. Lotus Notes is particularly prone to this problem.

If the reply includes enough of the original message, you may be able to determine who the recipient is. If not, the only recourse is to respond to the message, a time-consuming and inefficient solution.

Second, it’s impossible to determine which campaign the response relates to. The result is email responses, unsubscribe rates, and recipient profile data can’t be correlated with campaigns, splits, or segments. Aside from the loss of valuable business information, this can hamper answering inquiries or prevent successful unsubscribes.

Using a Dynamic Address

Dynamic response addresses solve both these problems. Dynamic addressing is performed by encoding campaign and recipient identifiers into the sender address of an email message. The reply then comes to an address unique to that recipient and campaign.

Yet dynamic addressing has its own shortcomings. Because the address changes with every message, recipients can’t add it to their address books. AOL, Hotmail, and some Microsoft email clients may mark email from unknown senders as potential spam.

Further, some recipients use challenge/response systems. These depend on static sender addresses to work effectively. Challenge/response systems keep a list of approved senders and challenge unrecognized addresses. Dynamic addresses are trapped by the system.

Finally, dynamic addresses aren’t very user friendly, and people are becoming increasingly suspicious of any address they don’t recognize. This can adversely affect campaigns.

The Best of Both Worlds

There is a way to address most of these issues and obtain the best of both worlds. Make the sender address static. It’ll be consistent, recognizable, branded, and easily added to a recipient’s address book. Make the reply address dynamic, encoding it with campaign and recipient identifiers. Any reply goes to the dynamic reply address and can be tracked to the campaign and recipient. This ensures you can immediately and accurately respond, regardless of forwarding or aliasing. It also allows you to track response and unsubscribe rates on a campaign, split, or segment basis.

This combined solution isn’t perfect. Your static address will receive email other than recipients’ responses. Some email systems ignore reply addresses. Though most email clients handle reply addresses correctly, a fair number of vacation autoresponders don’t. As a result, your static sender address will receive a significant number of vacation responses and some bounces that will need to be filtered. Viruses will pick up your static address from recipients’ address books. Your address will also start receiving spam. With good virus protection and sensible filtering, this should be a manageable problem.

By combining a static sender address with a dynamic reply address, you get the best of both worlds — the traceability of dynamic addressing with the consistency and user friendliness of static addressing.

Until next time.

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