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Inactive Subscribers: What's Your Strategy?

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by: Loren McDonald (@LorenMcDonald)
18 August 2010

Introduction: Why Bother?

Your email database might show big numbers, but 25 percent to 40 percent of your subscribers, or more, could be inactive without showing any obvious symptoms.

Their addresses are still valid. They simply aren't acting on your email messages anymore. Essentially, your content no longer attracts enough interest to compel these subscribers to act on your email messages. Or, perhaps, it never did.

Inactives have become the "silent majority" on many lists, or, as email expert Dela Quist calls them, the "unemotionally subscribed."

Your messages don't bounce; neither do they record any kind of activity, from opening to clicking, unsubscribing or even spam complaints.

Don't let this lack of action lull you into complacency or your own lack of action. Nonresponders can impact your email marketing program in three key ways:

  • Reduced Deliverability: ISPs are beginning to factor activity into the algorithms they use to determine whether to deliver or block email messages. Some turn inactive addresses associated with dormant accounts into spam traps. When you send to these addresses repeatedly, you risk getting blocked.
  • Muddied Performance Measurements: Including nonresponders in your metrics analysis depresses your email engagement and response rates and leads to muddied assessments of your email program's performance. This can hurt your ability to gain the commensurate budget and resources.
  • Resource Allocation: Although the per-message cost to send email is still comparatively low, sending messages to people that are unlikely to ever engage in the future may not be the best use of resources. These resources will deliver a better ROI when focused on the actively engaged.

So, do you just draw a line in the sand and hack off any subscriber who hasn't opened or clicked on your emails in the last six months? No, because you could end up losing subscribers that will purchase in the future and wasting the money you spent on acquisition.

It's better to develop strategies, first to identify and then to reach out to inactives before deciding their fate. See "Remove or Retain Inactives?" below for more on this hotly debated topic.

Who Are Your True Inactives?

Inactivity doesn't have a one-size-fits-all definition. Many email marketers use a simple guideline: six, nine or 12 months without any activity at all (opens and clicks). Some B2B marketers and long purchase-gap companies, such as auto and home loans, look at 5- and 7-year time frames. Others incorporate offline and purchase behavior. Many ISPs consider whether an email account itself shows any activity for six months.

A combination of metrics will give you the most accurate picture. If you use just one measure–the open rate, for example, or purchase history from emails–you'll exclude quietly engaged subscribers.

Prepare to dive deep into your database in order to find patterns and propensities that will help you draw up the most accurate definition of inactivity in your database.

How to Identify Inactives, Part 1

These factors can help you begin to set rules to segment out apparently inactive subscribers:

  • Email Activity: This alone will not give you an accurate list of inactive addresses, but it is a good start. Begin with addresses that recorded no activity since opt-in or within a logical time period using the factors listed below.
  • Frequency: If you send email infrequently (monthly or less often) you'll need to allow more time in your definition of inactivity.
  • Purchase Pattern: Do most customers typically purchase more than once over the course of a year or two, or do they typically buy only once every few years?
  • Number of sales channels: Online-only merchants will likely have a shorter inactivity definition than those who reach customers via multiple channels such as retail stores, catalogs/direct mail, social media, etc., where email can drive offline or off-channel purchases.
  • Purchase/activity history: Separate those who have previously made a purchase or completed a conversion activity from those who haven't.
  • Market environment: If you're in a highly competitive market or have a high-demand product, inactivity will show up earlier than if your market is slowing or transitioning.

Identifying Inactives, Part 2: Who Comes Back?

Before you finalize your definition of inactivity, analyze your database to determine the likelihood that apparent inactives could eventually come out of hibernation.

Go back at least two years and identify subscribers/customers who had no email activity for an extended time (at least six to 12 months depending on the factors listed above).

Now, review activity since then to see how many showed some sign of engagement: opening/clicking on an email, purchasing or converting in some way, changing profile data, etc. Also look at non-email activity, such as Web browsing, contacting customer support or requesting a print catalog. What was the total value or activity that these rebounders generated?

Look for behavior patterns. Did they buy similar products? Do they share similar demographics? Did they come from the same opt-in source? Were certain offers or campaigns more likely to draw them back?

Incorporate any customer data you have, including lifetime customer value, recency-frequency-monetary analysis, loyalty-program membership and the like.

This analysis will drive your organization's strategy and separate true inactives from those who are ripe for reactivation or may re-engage on their own.

The Big Debate: Remove or Retain Inactives?

Although most marketers agree that inactivity is a serious challenge, the industry seems divided over whether it's better to keep emailing inactives or to remove them from the active database.

Some refuse to remove inactives at all because their customers buy only infrequently, or they could come back to buy, convert or otherwise re-engage, or because an email message could drive an offline purchase. Another key argument is simply the brand value of email, like a billboard impression, that regularly appears in the consumer's inbox.

Those who regularly prune their lists of inactives prefer to keep focused on engaged subscribers, like the prospect of fewer deliverability problems and are confident that very few inactives will re-engage anytime soon.

The reality is that most subscribers go inactive because your email program is not delivering the kind of value they expect or aligned with their evolving needs and interests. So, before removing subscribers, make sure you've taken your email program up several notches in sophistication and value.

Your Four-Step Action Plan

These steps will help create a plan to deal with inactives, both to re-engage as many as possible and ultimately to move true inactives off your list.

1. Segment: Divide inactive subscribers into customers (those who purchased) and prospects (either no activity or just opened/click without purchase). Create tracks for various levels of value and engagement. Slot inactives according to your analyses and create messaging for each track.

Example:, the online fabric retailer and a Silverpop client, segments its database according to customer behavior, from most active to least active. It sends out offers customized to each segment and intended to keep loyal customers engaged and entice back inactives.

Read more in this case study.

2. Reactivate: Develop strategies for your various groups using any or a combination of the tactics below:

  • Invite subscribers to update preference forms
  • Offer a purchase incentive
  • Create emails promoting highly recommended items or items that fit with customers' previous purchases
  • Ask them to fill out a short survey on how your email program can better fit their needs and interests
  • Promote other email offerings you may have
  • Invite them to engage via social media channels or switch their communication preferences to print, SMS or other channels
  • Promote changes, updates, improvements to your website, email program or other outlets

All of these communications should include a prominent unsubscribe link and directions to offset any chance that the subscriber could just click the "report spam" button instead in an attempt to stop future emails.

3. Manage nonresponders: Here are some potential next steps for subscribers who don't respond to your reactivation overtures:

  • Move them into a nonresponder message stream with reduced frequency but more aggressive offers. Test subject lines in this group to find those that are more likely to move the needle.
  • Move them into a trigger-only track, so that they receive messages based only on demographic, preference or behavior matches (birthday, opt-in or purchase anniversary, product category or interest, wish lists, requesting catalog or customer-support contact, cart abandonment, offline purchase, etc.)
  • Send a stand-alone email inviting them to update preferences in order to continue receiving email messages or be removed.
  • Move them out of your active marketing database or suppress all future mailings. However, do this only after you are highly confident they will be unlikely to re-engage in the future and have met your criteria and comfort level established above.

4. Monitor and optimize: Track response rates in each of your re-engagement programs. Watch to see whether they generate a higher rate of spam complaints compared with your regular mailings.

Also, test every aspect of your program, including subject lines, offers, body copy, images, send times or days. Things that generate movement from your inactives could also energize your more active subscribers. Use this information to refine your messages or programs to produce even higher gains.

Minimize Future Inactivity

Ultimately, the most important part of your "inactives" program, is to implement strategies to minimize non-responders in the future. Below are some of the main reasons subscribers go inactive, along with potential solutions:

  • Source: A significant percentage of inactives might come from a single source or similar sources (e.g., incentive-based such as contests or downloads). Reconsider or refine your use of those list-building sources and tactics that have a high inactive percentage.
  • Opt-in process: Your email messages might not live up to what subscribers expected at opt-in. Review and test copy and layout, include links to sample emails, etc.
  • Welcome program: Dropping new subscribers into your standard broadcast messaging stream may contribute to inaction, especially if those messages don't meet expectations as explained above. Create a multi-step welcome program that warms up the subscriber to your brand and email messages and creates a good email impression at the start—before dropping them into your regular email track.
  • Early identification: The first 30 days after opt-in are the most critical in your new subscriber relationship. Yet, Silverpop's 2009 study of top Internet retailers found 22 percent sent no email in that period. This silence sets the stage for inactivity just as much as overmailing new subscribers.

Monitor subscriber activity closely for fall-off or failure to engage. Move those who register no activity into an early warning track, using surveys, invitations to create or update preferences, or incentives to engage them before they become unrecoverable.

  • Message variety: Even your most engaged subscribers will get bored when messages say only "Buy, buy, buy!" Alternate promotional email with surveys, preference updates, educational content and other messages to retain interest and spur activity.

Side benefit: You can use the information you collect to segment your database and target messaging, which makes your messages more valuable and fights inactivity.

  • Cross-promote: Subscribers go inactive when your email messages no longer speak to their interests and needs. If you offer multiple email newsletters and programs, cross-promote those too—a different program may resonate better with some subscribers.
  • Move to triggered messages: Supplement your broadcast email program with a selection of messages automatically triggered by demographic or preference matches or subscriber/customer behavior.

Conclusion: "No Action" is Not an Option

Subscriber inactivity is a big drain on your email program. It demands attention to ensure continued success of your program.

It doesn't matter whether you side with the "retainers" who elect not to remove inactives, or the "removers," who regularly prune their lists. You just have to act, whether it's to entice subscribers back to engagement or to create a judicious process to trim those who left without saying goodbye via unsubscribing.

You have invested significant staff time and budget to acquire your subscribers and to build a successful email program. Don't waste this precious investment.


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