I appear to have written a lot about about re-engagement on the Email Geeks slack channel the last few days. The problem with slack is it’s not great at archiving or keeping information in an accessible, searchable manner. So, I’ve pulled together the answers, rearranged it, made it slightly more coherent and a little less less stream of consciousness so I can reference this when it comes up again.

A little background

Most of my work with re-engaging users is with folks who have been listed on a blocklist due to spam trap hits or who are dealing with major deliverability problems at consumer mailbox providers like Google and Yahoo. I don’t normally recommend or even encourage clients without deliverability problems to run re-engagement campaigns. If things are working, there’s no reason to shrink your subscriber base. Re-engagement is something I use to solve a problem, not something I do ore recommend as ongoing practice. This is particularly true when there is real permission during the initial collection process. Re-engagement campaigns are needed less frequently when recipients give true consent, it’s not assumed or taken by the sender.

From my deliverability perspective re-engagement campaigns are intended to fix problems with addresses that will hurt your overall reputation and, eventually, your delivery at consumer mailbox providers. There’s three broad categories of addresses here:

• Abandoned email addresses: These are the kinds of addresses I talked about in my 2010 zombie series. The owners of these addresses legitimately and actively subscribed to a mailing list at some point and the addresses are still accepting email. However, the owner has abandoned the email address, either intentionally or accidentally by losing a password. The mail may be going to the inbox or the spam folder, the sender just doesn’t know. In some ways these can be thought of as “proto” or “partial” spamtraps.
• Addresses where the mail is going to the spam folder: This category is pretty self explanatory. When mail goes to the spam folder, that’s a negative hit against reputation. Even if it was the mailbox provider that put the mail into the spam folder, it still acts as a negative hit to the ongoing reputation measurement.
• Actual spam trap addresses: Again pretty self-explanatory category, but I have a couple deep dive posts into spamtraps from earlier this year (Do Spamtraps Exist and What Spamtraps Tell Us). In this case we’re really talking about pristine or recycled taps.

In general, the addresses in these 3 broad categories will show no interaction - no pre-fetching, no image loads, no clicks. They’re black holes in terms of engagement. But actual addresses can also exhibit the same (lack of) characteristics. In those cases there might be real recipients at the address, but we can’t measure it. Which brings me to discussing the different kinds of engagement.

• Engagement as measured by the sender: This is what most senders think of as engagement. It’s opens / image fetches and links visited.
• Engagement as measured by the recipient mailbox provider: This is an individual user interacting with the messages in a context where the mailbox provider can measure the interaction. This includes users who read and interact with mail through the web interface or through dedicated apps published by those mailbox providers on various devices. For the most part, this is mostly measured by the large US based mailbox providers, so Google, Microsoft, or Yahoo consumer or business mailboxes. Apple goes out of their way to avoid connecting activity to the user as Steve documented in 2021 in his Apple MPP post.
• Engagement with the product or the brand by the user that is unmeasurable: So, if I configure my mail client to not prefetch images I can open and read mail without sending a signal to the sender. I can also choose to visit the website through my bookmarks or directly going to the site without clicking in the email. I’m still engaged with that brand, but the sender cannot directly measure that effect.

Crafting the campaign

As I said above, I do re-engagement campaigns as part of fixing specific deliverability problems. Typically I’m helping a client recover from a Spamhaus or other kind of block. My “re-engagement” campaigns are more “let’s get rid of all the spam traps” campaigns. I initially bucket folks into “absolutely, this is a real subscriber and we have XYZ data to confirm it, so we aren’t going to put them in the re-engagement campaign” and “we have zero evidence this is a real subscriber and have never, ever seen any activity from them, so we’re going to just not even bother” and “everyone else”. Then we look at what data the client has about “everyone else” and develop a way to send them mail to see if a) they’re a real person, b) they’re getting mail from the client in their inbox and way, way, way down the list c) are they going to ask to continue to get mail from my client.

I also consider the domains we’re sending to. As I said above, engagement as a filtering criteria is more prevalent at the commercial mailbox providers in the US. So we’ll also look at the list make up and maybe only do re-engagement on a limited, carefully chosen population.

Personally, I believe that there are maybe 10 - 20% of folks who have image loading turned off. In my experience Google and Yahoo open rates are around 30 - 40%. I think this number would be higher if more people had pre-fetching turned on. But that’s a whole different long blog post.

Considerations

When we think about re-engagement, we need to think about what we’re really trying to do here. Are we trying to clear off potential spamtraps and folks who are getting mail in their spam folder, cool. Let’s do one kind of re-engagement campaign. Are we trying to send mail to a list we’ve been collecting for an age, but haven’t used? OK, we can do a different kind of re-engagement campaign. Are we just trying to remove folks who aren’t going to pay us immediately? Let’s do this other kind of campaign.

When crafting a strategy for clients I take all of the above things into account. In addition, I try and remember people can engage with a brand or a marketing email in ways that can’t be tracked by marketers. It’s like TV advertising or billboards or whatever. The people see the mail, and make a purchase or whatever without doing it in a way that can be tracked directly to that email address. Some of this type of mail isn’t isn’t straight marketing but is more like newsletters and news alerts and other types of messages that don’t actually involve purchasing something. This can be considered “unengaged” but I don’t believe it hurts deliverability in the long term if the overall email program is well liked by the recipient base. To be fair, I only have a qualitative feel for this data based on 20-some-odd years of looking at deliverability. I’ve never done an actual controlled study of things. I could be wrong here, but I see a lot of senders with what looks like ‘poor’ engagement, but with perfectly fine delivery.

Where did this start?

The original question was, essentially: I want to make sure un-engaged addresses don’t hurt my deliverability, so what type of re-engagement campaign do you recommend for addresses that haven’t engaged in 60 - 120 days? Can I just use opens to count a user as ’engaged’?

I went down the rabbit hole of explaining so much because the question spoke of someone who had been doing their research and thinking a lot about how to manage their deliverability. They had clearly been doing their research and were trying to integrate a lot of knowlege into a strategy. But the question itself also spoke how badly people explain deliverability recommendations. I am also seeing a lot of mis-information about deliverability, written by people who don’t understand the space and/or who are just outsourcing all their writing to AI.

After all of the explanation, I got to the actual answer: To my mind the biggest problem with unengaged users are those that are getting the mail in their spam folder or those addresses which are abandoned. I honestly don’t think there’s a huge problem with a user who gets mail in their inbox and only looks at it every few months. When we’re dealing with unengaged users, we’re mostly trying to keep those classes of users as small a proportion of our recipient base as possible.

Final Thoughts

Re-engagement campaigns should serve a purpose. They will lose you actual subscribers, some of whom might still want your mail even if you can’t tell that because they’re blocking image loads or because your ESP removes “NHI opens” or “Bot Clicks”. You don’t need to do regular re-engagement campaigns just like you don’t need to clean your list on a monthly basis. These processes are designed to remove recipients from your list, and some of them are going to remove actual, real, valuable subscribers. These processes should be implemented with specific goals in mind, not just because you read a blog post somewhere that said it might be a good idea.