Zombie email: Part 2

In zombie email: part 1 I talked about how email addresses were tightly tied to internet access in the very early years of the internet. We didn’t have to worry about zombie email addresses because when an account was shut down, or ignored for a long time then mail would start bouncing and a sender could stop sending to that account.
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)

Related Posts

Content based filtering

A spam filter looks at many things when it’s deciding whether or not to deliver a message to the recipients inbox, usually divided into two broad categories – the behaviour of the sender and the content of the message.
When we talk about sender behaviour we’ll often dive headfirst into the technical details of how that’s monitored and tracked – history of mail from the same IP address, SPF records, good reverse DNS, send rates and ramping, polite SMTP level behaviour, DKIM and domain-based reputation and so on. If all of those are OK and the mail still doesn’t get delivered then you might throw up your hands, fall back on “it’s content-based filtering” and not leave it at that.
There’s just as much detail and scope for diagnosis in content-based filtering, though, it’s just a bit more complex, so some delivery folks tend to gloss over it. If you’re sending mail that people want to receive, you’re sure you’re sending the mail technically correctly and you have a decent reputation as a sender then it’s time to look at the content.
You want your mail to look just like wanted mail from reputable, competent senders and to look different to unwanted mail, viruses, phishing emails, botnet spoor and so on. And not just to mechanical spam filters – if a postmaster looks at your email, you want it to look clean, honest and competently put together to them too.
Some of the distinctive content differences between wanted and unwanted email are due to the content as written by the sender, some of them are due to senders of unwanted email trying to hide their identity or their content, but many of them are due to the different quality software used to send each sort of mail. Mail clients used by individuals, and content composition software used by high quality ESPs tends to be well written and complies with both the email and MIME RFCs, and the unwritten best common practices for email composition. The software used by spammers, botnets, viruses and low quality ESPs tends not to do so well.
Here’s a (partial) list of some of the things to consider:

Read More

Delivery consulting: it's all about the credibility

A few months ago I found a great blog post written by an ER doctor about how to convince other doctors to come in and deal with a patient in the middle of the night. There are quite  few similarities between his advice and the advice I would give delivery experts, ISP relations folks and ESP representatives when dealing with ISPs and spam filtering companies.

Read More

Email marketing is hard

I’ve watched a couple discussions around the email and anti-spam community recently with a bit of awe. It seems many email marketers are admitting they are powerless to actually implement all the good advice they give to others.
They are admitting they can’t persuade, cajole, influence or pressure their companies to actually follow best practices. Some of the comments public and private comments I’ve heard from various industry leaders:

Read More