Thoughts on Data Hygiene

One 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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It's not about the spamtraps

I’ve talked about spamtraps in the past but they keep coming up in so many different discussions I have with people about delivery that I feel the need to write another blog post about them.
Spamtraps are …
… addresses that did not or could not sign up to receive mail from a sender.
… often mistakenly entered into signup forms (typos or people who don’t know their email addresses).
… often found on older lists.
… sometimes scraped off websites and sold by list brokers.
… sometimes caused by terrible bounce management.
… only a symptom …

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Zombie email: Part 3

Last week, in Zombie email: part 1 and part 2 I talked a little about the history of email addresses and how changes in the ISP industry in the early to mid 2000’s brought about the rise of zombie email addresses. Today we’ll look at the effect zombie addresses have on email stats and why ISPs are starting to monitor zombie addresses.
A zombie address, despite the fervent belief of some email marketers, doesn’t come back to life. The person who initially registered that address has decided to stop using that email address.  The defining factor of a zombie address is that there isn’t now and won’t be anyone in the future reading email sent to that address. There is no human there to read or react to any email sent to that address.
A zombie address does not represent an actual recipient, they’re just remnants of a recipient that once was present.
Having a list containing any significant number of zombie addresses can throw off metrics enough to mislead a sender about the effectiveness of their email marketing program. Sometimes, the zombie addresses make the metrics look worse, sometimes they make metrics look better. In either case, the metrics don’t accurately represent the performance of a marketing program.
Zombie email addresses do bulk out a mailing list, making lists look bigger. They’re not real addresses, so they don’t reflect quality, but they do impress marketers that think bigger is always better. But, in reality, you may as well add thousands of addresses at non-existent domains for the real value these addresses bring to your list.
Zombie email addresses on a list depresses any metric that use “number of emails sent” or “number of emails accepted” as a denominator.  If 10% of a list is zombie addresses, then an open rate reported as 15% will actually be an open rate of 16.7%. The more zombie addresses on a list, the more the statistics will be depressed.
In addition to having lower open rates, lists with more zombie addresses also have a lower complaint rate. In fact, in the recent past spammers have padded their lists with zombie addresses as a way to artificially lower their complaint rates.
Spammers using addresses created just to bulk up the denominator and lower complaint rates have led ISPs to start monitoring the types of addresses on a particular list. I first heard about ISPs looking at recipient profiles at a meeting in 2006, so it is not, in any way, a new technique for ISPs. What is new is the number of zombie addresses on legitimate, well maintained lists, and the fact that they are present in high enough volume to affect reputation and delivery.
ISPs use zombie addresses to monitor the reputation of a sender because it is a more accurate way to measure what the recipients think about an email and that sender. Senders ignore zombie addresses because they make some stats look bigger (total list size) and better (lower complaint rates). Many senders also believe that addresses come back to life, despite all evidence to the contrary, and will not purge an address for any reason other than it bounces. They’d rather live with inaccurate and misleading metrics than removing non-performing addresses.
Tomorrow, in the final post of this series, we’ll examine how senders can identify potential zombie addresses and what steps they can take protect themselves from the negative reputation hit from zombie addresses. (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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