It’s a good read, and I strongly encourage everyone to go give it a look.

But his post led me to a post by Andrew Kordek at Trendline where he claims that there is an industry rule of thumb that says 6 months is the rule of thumb to define an inactive.

Wait, What?

I know there’s a huge amount of controversy in the email space about whether or not you should purge inactive addresses. I know there are some very vocal people who think that removing inactive addresses is tantamount to marketing suicide. But where did 6 months come from? Who made it an industry standard?

If we don’t know where the standard came from, if we don’t know why we’re doing it then what kind of mickey mouse industry are we running here?

There is a lot about email marketing that is empirical. You poke the black box on one side and see what happens on the other. The problem with that is, that we can “discover” a lot of effects that aren’t real, but somehow turn into “you must do this!”

I have no doubt there are times when a 6 month expiry is a good idea. A number of my clients over the last few years use a much, much shorter time because that’s what works for them. I also know there are times when longer expiry times are a good idea, too.

It’s really important that when you’re making decisions about your email marketing program that you don’t mindlessly apply “standards” to what you’re doing. Think about the practical effects of your decisions and put them in context with your overall business plan.

To do otherwise is to kneecap your email marketing program.

If you haven’t mailed an address in 5-10 yrs, would you include it in a re-engagement mail?

A number of people responded that addresses that old should not be mailed. I think the answer is more complex than can be handled in 140 characters.

Five to ten years is a very long time. Think about what you were doing 10 years ago. It’s easy right now, 10 years ago as a nation we were still reeling from the September 11 attacks. On a more personal note, Steve and I were just making the decision to start Word to the Wise. But what about 5 years ago? I can’t remember what we were doing or what our business goals and limitations were.

If you’re going to mail addresses that were collected 5 or 10 years ago, you must give some thought to a number of questions.

1. How has my target market changed in the last 5 – 10 years? How likely is it that customers from then would be interested in my products now?

People grow and change. As we move through different life stages, we have different needs and shop for different products. When thinking about whether or not to send mail to those old addresses, think about customer demographics. Is someone who wanted your product in the past also going to want your product now? What life stages are you targeting?

If you can honestly say that your product has a 10+ year target market, then mailing old customers may be acceptable. But if you focus on a narrow demographic it’s possible that your former customers are no longer interested in anything you have to offer, no matter how compelling the copy.

2. What do I have to offer a customer from 5 – 10 years ago? Is my current product line likely to interest them?

Just as people grow and change, businesses grow and change as well. When we first started Word to the Wise a lot of my consulting was directed at senders who were having blocklist problems and often didn’t have permission to send the mail they were sending. We didn’t have to talk about bulk folders, as most major ISPs hadn’t adopted the bulk folder yet. We didn’t have to talk about Feedback loops or “this is spam” buttons because such things didn’t exist yet. They primarily wanted to know how I could help them get and stay off the RBL or SBL.  In contrast, most of my current customers are opt-in senders who want information about how to engage users and get a better responses to their email.

Sure, old customers may be interested in new products and re-establishing contact with an old vendor. Others may have no interest at all. Some small percentage having an interest in your product isn’t sufficient. You need to be sure that a large percentage of recipients are going to want your new product.

3. How long does my product last? Are older customers still interacting with my product? Or have they forgotten I even existed?

There are pieces of software I’m using from 5 or 10 years ago. I’d be fine with a re-engagement email letting me know about other offers they have. But there are also bits of software I downloaded, tried and promptly forgot. I’d be annoyed if the vendor tried to email me. That really nifty pepper mill we bought 6 years ago? Love to hear from them about new stuff. That random kitchen gadget gathering dust in the back of a drawer? Not so much.

So much of making decisions about email is gauging how receptive recipients are to your message. When trying to decide to email very old customers, it’s important to understand your previous customer base.

4. What value am I bringing to the recipient? Do I have something new to offer? Can I push a new product or new launch?

The core of email deliverability is sending mail that your recipients want to receive. If you’re contacting recipients that haven’t heard from you in years, you need to put extra effort into making the email relevant for their lives. One of the ways you can do that is to share your excitement with a new product line, or a re-brand of your company.

Another way to make the email relevant is to make the email informative. Talk to the recipient about how you’ve changed in the intervening years and how your products can help the recipient. Your old customers are more likely to accept your intrusion if you have useful information for them  with your old customers

5. Where did I get these email addresses? Do I have a good audit trail for them?

This is where we get to those pesky details. Do you actually know where the addresses came from? Do you have even a partial audit trail. Can you tell what product was bought by the address? Do you know when the address was entered into your database? Do you even know if these are addresses of customers or not?

In my experience, most companies don’t have good audit trails for older addresses. They don’t know where the addresses came from. They don’t know if they’re actual customers. These are the things that cause re-engagement to fail totally.

You should NEVER mail old addresses unless you can identify where the address came from and the specific purchase that address is associated with. If you don’t have that data, then your delivery is going to be awful. You can only aspire to get into the bulk folder. More likely, you’re going to end up with mail blocked at many ISPs.

For the sake of argument, let’s say you do have that data. Someone at your company set up a database that captured everything you may need to mail old customers.

It’s not enough to have the audit data, you should take a deep dive into the data itself. How many of the addresses are at any of the dozens of domains that have retired in the last 10 years? How many are @home.com, @attbi.com, homestead.com or mcimail.com? None of these domains exist any longer. How many are @compuserv.com, @prodigy.net or earthlink.net? These are domains that were popular long ago, but are no longer in wide use. It’s unlikely your customer still has that address.

Still thinking about mailing that list, because it’s mostly @aol.com or @hotmail.com addresses? That may still risk your delivery. Old addresses at major domains are often turned into spamtraps and mailing these addresses may result in blocking.

Statistics show that 30% of email addresses are abandoned by their owners in a year. That means that even 5 years back only about 20% of those addresses are still in use by your customers. The others are abandoned, turned into spamtraps or just won’t deliver. If 80% of your list goes into a black hole, how much does each sale have to be to make it profitable to contact those old customers?

Each question should take an average business quite a bit of time to answer. The first 3 questions are about the intersection between you and your customer. They’re about you, the business, honestly evaluating your product (then and now), your target market (then and now) and the chance that you will meet their needs now as you met them then. The fourth question is about what you want to tell your old customers. But none of those questions are even worth asking unless you know you have a database worth sending to. And even if you do, will the ROI on a mailing be enough to justify the expense to put together an effective re-engagement campaign?

I got email today to an old work email address of mine from Strongmail. To be fair it was a technically correct email. Everything one would expect from a company handling large volumes of emails.  It’s clear that time and energy was put into the technical setup of the send. If only they had put even half that effort into deciding who to send the email to. Sadly, they didn’t.

My first thought, upon receiving the mail, was that some new, eager employee bought a very old and crufty list somewhere. Because Strongmail has a reputation for being responsible mailers, I sent them a copy of the email to abuse@. I figured they’d want to know that they had a new sales / marketing person who was doing some bad stuff.

I know how frustrating handling abuse@ can be, so I try to be short and sweet in my complaints. For this one, I simply said, “Someone at Strongmail has appended, harvested or otherwise acquired an old email address of mine. This has been added to your mailing list and I’m now receiving spam from you. ”

They respond with an email that starts with:

“Thank you for your thoughtful response to our opt-in request. On occasion, we provide members of our database with the opportunity to opt-in to receive email marketing communications from us.”

Wait. What? Members of our database? How did this address get into your database?

“I can’t be sure from our records but it looks like someone from StrongMail reached out to you several years ago.  It’s helpful that you let us know to unsubscribe you.  Thank you again.”

There you have it. According to the person answering email at abuse@ Strongmail they sent me a message because they had sent mail to me in the past. Is that really what you did? Send mail to very old email addresses because someone, at some point in the past, sent mail to that address? And you don’t know when, don’t know where the address came from, don’t know how it was acquired, but decided to reach out to me?

How many bad practices can you mix into a single send, Strongmail? Sending mail to addresses where you don’t know how you got them? Sending mail to addresses that you got at least 6 years ago? Sending mail to addresses that were never opted-in to any of your mail? And when people point out, gently and subtly, that maybe this is a bad idea, you just add them to your global suppression list?

Oh. Wait. I know what you’re going to tell me. All of your bad practices don’t count because this was an ‘opt-in’ request. People who didn’t want the mail didn’t have to do anything, therefore there is no reason not to spam them! They ignore it and they are dropped from your list. Except it doesn’t work that way. Double opt-in requests to someone has asked to be subscribed or is an active customer or prospect is one thing. Requests sent to addresses of unknown provenance are still spam.

Just for the record, I have a good idea of where they got my address. Many years ago Strongmail approached Word to the Wise to explore a potential partnership. We would work with and through Strongmail to provide delivery consulting and best practices advice for their customers. As part of this process we did exchange business cards with a number of Strongmail employees. I suspect those cards were left in a desk when the employees moved on. Whoever got that desk, or cleaned it out, found  those cards and added them to the ‘member database.’

But wait! It gets even better. Strongmail was sending me this mail, so that they could get permission to send me email about Email and Social Media Marketing Best Practices. I’m almost tempted to sign up to provide me unending blog fodder for my new series entitled “Don’t do this!”

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.

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)

There were two major changes to email accounts in the early 2000′s that led to the rise of zombie emails.

People started decoupling their internet access from their email addresses. Free addresses were easy to get and could be checked from everywhere. No longer did they have to dial in to get email, they could access it from outside the office and outside the home. Mobile devices, including the first generation of smart phones and laptops, helped drive people to use email addresses that they could access from any network. The easy access to free mail accounts and the permanence led people to adopt those addresses as their primary address.

When people changed addresses, for whatever reason, they didn’t have to stop paying. There was no way to tell the free ISPs to stop accepting mail for that address. Free mail providers would let addresses linger for months or years after the user had stopped logging in. Sometimes those addresses would fill up and start bouncing email, but they were not often turned off by the ISPs.

The lack of purging of abandoned addresses was the start of dead addresses accumulating on mailing lists. But there weren’t that many addresses in this state, and eventually they would fill up with mail. When they were full the ISP would stop accepting new mail for that account, and the address would bounce off a mailing list.

Everything changed with the entrance of Gmail onto the scene. When Gmail launched in 2004 they were providing a whole GB of storage for email accounts a totally unheard of storage capacity. Within a year they were providing multiple gigabytes of storage. Other freemail systems followed Gmail’s lead and now all free accounts have nearly unlimited storage. Plus, any mail in the spam folder was purged after a few weeks and bulk mail doesn’t count against the users’ storage quota. Now, an abandoned email account will almost never fill up thus senders can’t use over quota bounces to identify abandoned accounts.

Now we’re stuck in a situation where SMTP replies can’t be used to identify that there is no one home inside a particular email account. Senders can’t distinguish between a quiet subscriber and an abandoned address. ISPs, however, can and are using zombie addresses as a measure of a senders reputation.

On Monday we’ll talk about why and how zombie addresses can affect delivery. (Zombie emails: part 3)

Tuesday, we’ll talk about strategies to protect your list from being taken over by zombies. (Zombie Apocalypse)

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

In a recent survey published by Help Net Security, approximately half of all employees said they would take data, including customer data, when leaving a job.

This has major implications for ESPs, where employees have access to customer data and mailing lists. There are at least 2 cases that I am aware of where employees have walked out of a company with customer mailing lists, and I’m sure there are other incidents.

ESPs should take action to prevent employees from stealing customer data.

Talking to clients and other industry folks, it looks like the addresses that have newly bounced off had zero activity for at least 6 months. Nothing. Nada. No clicks. No opens. No interaction.

This is why data hygiene is so critical. Just because the emails are being accepted at the ISP, and even showing inbox placement at the mailbox monitoring companies does not mean that there is actually someone reading your email. Failure to look at overall data means that when an ISP bulk deletes abandoned accounts then bounces will increase. While I don’t expect this to have any real, long term effect on sender reputation I do expect that some senders with a lot of cruft on their list will see some short term delivery problems.

Companies that run re-engagement campaigns saw a whole lot less bouncing and even less blocking as a result of the purge. They were removing addresses that were non-responsive all along and thus didn’t have major deadwood on their list.

Ongoing data hygiene shows you what your list really is, not your list plus abandoned accounts. The addresses that the ISP purged? They were not valuable anyway. No one was reading that mail for at least 6 months.

If you did see a spike in bounces this weekend at a major ISP, you should really look at engagement. If some percentage of recipients at one ISP are actually non-existent, then it’s likely that about that same number are non-existent at other major ISPs as well. What are you going to do to identify and remove those dead addresses from your lists?