Thoughts on Data Hygiene

zombieemailOne of the big deliverability vs. marketing arguments has to do with data hygiene and dropping inactive users. Marketers hate that deliverability people tell them to let subscribers go after a long time of no activity from the subscriber.
Data hygiene is good. Email is not permanent and not forever, and the requirements for data hygiene in the email space are very different than the requirements in the postal mail space. There is no such thing as “dear occupant” in email. I mean, you can sent to occupant, but the occupant can then hit the this is spam button. Too many emails to “occupant” and mail goes to bulk instead of the inbox. These are real risks.
With that being said, there are a lot of things to consider when putting together a data hygiene program. You’re looking to remove people who are no longer interested in your brand as much as they are no longer interested in your mail. You’re trying to suss out who might have abandoned the email address you have for them. It’s complicated.
I’ve worked with a lot of clients over the years to implement data hygiene programs. Sometimes those programs were to deal with a bulk foldering issue. Other times clients have been trying to address a SBL listing. Still other clients were just looking for better control over their email and delivery. In all cases, my goal is to identify and classify their recipients into 3 groups: addresses we know are good, addresses we know are bad, and then addresses we don’t know about.
Good addresses get mailed. Bad addresses get dumped. The challenging bit is what do we do with the unknown addresses? That’s when we start looking at other data the client may have. Purchases? Website visits? What do we have to work with and what else do we know about the people behind the addresses. Once we’ve looked at the data we design a program to take the addresses we don’t know about and drop them into either the good or the bad bucket. How we do that really depends on the specifics of the company, their program and their data. But we’ve had good success overall.
There’s been a lot of discussion on hygiene this week, after Mailchimp published a blog post looking at the value of inactive subscribers. They found something that I don’t find very surprising, based on my observations across hundreds of clients over the years.

[T]he data backs it up: An inactive subscriber is a better customer than a non-subscriber.

This actually came up at the MessageSystems Insight Conference in Monterey last year. One of the MailChimp guys asked me about pruning during my talk. Afterwards, we had a conversation at dinner. He said MailChimp was looking at changing their recommendations and asked my opinion on the blanket ‘prune your subscribers’ recommendation. Specifically he wanted to know what I thought about it in the case of retailers.
I told him I’d never held on to the idea that a company should just prune subscribers from a list in the absence of delivery problems. If the users are not hurting delivery, there really isn’t a reason to drop them. Remember, ISPs measure engagement differently than marketers, so they may be engaging with the mail in ways senders can’t track.
I do think there is some point where a sender should give up mailing, but that is really going to depend on the sender and their process. Newsletters vs. advertising vs. retail vs. e-commerce have different customer and product lifespans.
What you’re selling matters, too. Cars have a different lifespan than light bulbs or toothpaste. If you’re selling something with a short interval and a customer hasn’t purchased in 4 or 5 or 6 cycles, maybe you should decide this isn’t a customer any longer. But if you’re selling cars someone may wait 4 or 5 years between purchases.
There’s also the data you started with. How did you initially acquire the customer? That also impacts how an address affects your deliverability. Some subscription pathways are going to be riskier and should be taken off your list sooner than others.
As with everything in deliverability, there is no one answer to when to stop mailing an address. It really does all depend on the specifics.
I’m glad MC did the work. I didn’t know our conversation over drinks was going to lead to such interesting data.

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Zombie email: Part 1

Zombie email addresses: those email addresses that never really die, eat your brains and destroy your email delivery. To understand zombie addresses and why they’re just now becoming a problem, we really need to understand some of the history of email addresses.
In the early days of the net, people got an email address usually associated directly with their access to the Internet. Many of them ended with .edu or .gov. I even had one that ended in .BITNET for a while. The first ISPs followed this convention. Users signed up for an account at a local dialup and were assigned an email address, and that was their email address. It wasn’t until the late 1990’s where there was widespread access to multiple email addresses.
What this means is that when people left a job, or canceled their Internet access their email address went away. Addresses that were abandoned would, after a short period of time, start bouncing back with user unknown, giving everyone the opportunity to stop mailing that account.
Even with the advent of multiple addresses for a single account and the easy availability of free addresses from places like Hotmail addresses that had been abandoned would still bounce off a list. Why? Because accounts had limited storage. My first dialup account had, I think, 10MB of space. It may have been as much as 20MB, but it wasn’t very much. Accounts receiving a lot of mail that weren’t checked frequently would fill up and start bouncing mail. Senders would be able to remove abandoned accounts because they were full.
Tomorrow we’ll talk about two things happened in the early 2000’s that changed email and led to the rise of zombie email.
Zombie Email: Part 2
Zombie Email: Part 3
Zombie Apocalypse

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Zombie Apocalypse

I hope my series on zombie addresses has convinced you that there are zombie addresses on your list and that you should be concerned about the effect they have on delivery and metrics. Today I’d like to talk about what you can do to get rid of zombie addresses without affecting too many actual subscribers.
Anti-Zombie Weapons
One thing that many companies struggle with while dealing with zombie addresses is letting go of addresses. They are so tied up in the idea that a bigger list is better that they can’t let them go. Even if a particular address has not had any activity in 18 or 24 months, they insist that they can’t give it up, it might come back and the customer might make a giant purchase. No. It’s a zombie. It’s not coming back, except to eat your brains.
The first step to dealing with zombies is to acknowledge their existence. They are there, they are on your lists and they are dirtying up your lists. Pretending they’re not there does not make them go away. They are zombies. In no case is there a human inside. There is no potential sale lurking, waiting to jump out and act on that perfectly crafted offer.
The second thing to remember is that the humans that used to have the zombie addresses found you once and they are still interested in what you’re offering then they will find you again. They may even already be back on your list with their new email address.
While you can’t identify zombie addresses specifically, you can identify addresses that act like zombie addresses. These are addresses that have no activity over a long period of time, more than 12 months. For these addresses that haven’t had activity in 12 – 18 – 24 months, you want to confirm with the recipient that they are there and want to continue to receive mail from you.
The best way to notify them is to send an email asking if they want to remain on your list. If they fail to act, you will remove them from future mailings. Short, sweet and will let you drop off zombie addresses without much effort on your part.
I know, I know, you aren’t ready to let go so fast. After all, some people have come back after 24 months and made a purchase from the perfect offer. They’re not dead yet! OK. But you can’t get a response from them through email. They just don’t care enough about what you’re sending. That’s when you contact them through another channel.
For instance, if the email address is tied to a web account, say a social networking site or bank account or a web forum, you can also contact the user through your website. Next time they log in, send them a message that says their email address has been removed due to inactivity, but if they want to reactivate they can do so at the subscriber preference center or profile page. When they do, send them an email to confirm that this is the address where they want to receive mail. At this point you can give them a link or a magic cookie to past into the website to verify the address.
Or if you’re a bigger retailer you can send alerts to your customer service staff, so when the account holder contacts you by phone with a question or an order you can get an updated email address. If you have a loyalty program, have an alert come up at the point of sale and the clerk can ask for an updated email address.
I even know one company that would send postcards to their zombie accounts in an effort to re-engage them and get an active email address from them.
If the person never comes back, if they don’t ever interact with your business again, if none of the channels work to contact them and update the address then it really is best to just let the relationship go. It may not be you, or anything you’ve done. People move on, their interests change and that’s part of life. They may have moved outside of your service area, or they may have joined your list for a specific product that they don’t need or you don’t sell. They may have died and turned into a real zombie. In any case, they are not a viable prospect for your mail.
Email addresses and business relationships are not forever. Letting zombie addresses go is important for the health of any email marketing program.

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Data hygiene

I talk about data hygiene with clients a lot. In my experience, poor data hygiene is the number one reason that legitimate, permission based marketing ends up in the junk folder. Too many marketers don’t remove abandoned addresses from their mailing lists. As the abandoned addresses build up, eventually the list accumulates enough zombie addresses that it looks similar to a spammer’s list.
I’ve talked in depth about zombie accounts previously (part 1, part 2, part 3, apocalypse) and they talk a lot more about why we have zombies accounts and why they’re just starting to be a bigger issue for marketers. Not only are we just starting to hit critical mass with zombie accounts, but ISPs are really starting to weigh engagement in their delivery decisions. Zombie accounts are not engaged with mail. Heck, they’re not even engaged with their own email addresses.
Many marketers, though, hate the idea of data hygiene. They hate thinking about losing a potential customer. They can show me numbers that say someone didn’t open an email for 18 months and then spent hundreds of dollars on a purchase. Or they can tell me that 10% of their revenue came from people who hadn’t opened an email in more than 12 months.
I don’t want to take those subscribers away from you, the ones who are engaged with your brand or your mail in some un-trackable way. But I do want to stop the zombies from eating your delivery.

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