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Data hygiene and bouncing zombies

There are a number of folks who tell me there can be no zombie addresses on their lists, they aggressively remove any address that bounces. The problem is that zombie addresses don’t bounce, at least not always. And even when ISPs say they have a policy to bounce email after a certain period of time with no access, that’s not always put into practice.
How do I know that ISPs don’t always deactivate addresses on the schedules they publish? Because I have seen addresses not be deactivated.
I have addresses in a lot of places that I go for long periods of time not checking. It’s rare that they’re taken from me or reject mail – most of the time they’re special test addresses I use when diagnosing issues. This post is based on my experiences with those addresses and how abandoned addresses are treated at some ISPs.
For Gmail I have two examples of addresses not being deactivated.
In July 2011, we set up a test address to look at how Gmail was handling authentication. We sent a matrix of different test emails to it, with valid and invalid SPF and DKIM signatures. We pulled the data from the account. I don’t know for certain when the last time I logged in, but it was August or September of last year. So we have an address that has been dormant since September 2011.
I just sent mail to the account and google happily accepted it.
Mar  2 07:03:22 misc postfix/smtp[11770]: 11CA12DED3: to=<wttwtestacct@gmail.com>, relay=gmail-smtp-in.l.google.com[74.125.127.27]:25, delay=1.8, delays=0.25/0.02/0.56/0.93, dsn=2.0.0, status=sent (250 2.0.0 OK 1330700602 x8si8608852pbi.66)
I have another google account (apparently) that my records show I set up sometime in 2010. The login info was saved October 2010. I don’t know when the last time I logged in was, but given I’d forgotten the existence of the account it’s a good bet that it has been more than a year. That account is also accepting mail as of today.
Mar  2 07:06:25 misc postfix/smtp[11836]: 8D90C2DED3: to=<phphendrie@gmail.com>, relay=gmail-smtp-in.l.google.com[74.125.127.27]:25, delay=1.6, delays=0.26/0.02/0.68/0.66, dsn=2.0.0, status=sent (250 2.0.0 OK 1330700785 a8si4075740icw.96)
For Hotmail I also have quite a bit of history and information. I signed up for my first Hotmail account in 1997. That was an account I used the address to post to usenet, but I didn’t actually use it for mail. I’d check it occasionally (usually when someone said in the newsgroup that they were going to email me) but it wasn’t an address I used regularly. As I moved from posting regularly in usenet, I started checking that account even less.
For a while, if I went more than 6 months checking my Hotmail account they would make me “re-claim” it. What would happen when I’d log in is I’d get a message along the lines of “well, we disabled this account due to inactivity, do you want it back?” I’d say yes, have to go through the setup process again and it would be my account. Mail was deleted during the disabling, and I am guessing they rejected anything new going to that account. I went through this dance for 4 or 5 years. I even had my calendar set to remind me to login every 6 months or so. There was some sentimental value to the address that kept me logging in. I have that same username at every major free ISP: Gmail, Hotmail, Yahoo and AOL, so it’s “my” address.
About 6 or 7 years ago, that behavior changed. I stopped getting the request to reclaim my account. Instead I could just log in. I’d still have mail (mostly spam as the address is on *lots* of lists and millions CDs). I still check it irregularly. I don’t have any idea when the last time I checked it was, but I think it’s been since at least November and probably longer back than that. Hotmail is still accepting mail for that address as well.
It’s anecdotal evidence, at best, but it ‘s the type of evidence that is acceptable even when it’s anecdotal. There are some addresses that are abandoned for long periods of time at the free mailbox providers and they’re are not all automatically pulled from the ranks of active addresses.
What does this mean for senders? It means that data hygiene has to go beyond just removing addresses that bounce. ISPs are not disabling addresses consistently enough for marketers to be able to trust that all addresses on their list are active just because they are accepting email.
This is the root of the recommendation to put in a hygiene program, this is why senders need to look at who is actually engaged with their brand and make some hard decisions about shooting zombies in the head.

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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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It would be nice…

It’d be nice to have a tool to uncover the zombie email addys, but until then, read this from @wise_laura: http://bit.ly/jxjZ9M Kelly Lorenz

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