Delivery Essentials

The silent killer hiding in your old email list

“…details at eleven.”

351px-Villainc.svgIf you grew up watching local news broadcasts in the ’80s, you probably recall the teasers touting all sorts of hidden dangers that could affect your family. And of course, when the payoff came, there was a sigh of relief as we all realized the story was blown way out of proportion – merely a ploy to raise ratings. Fortunately for us, our pantries, medicine cabinets, and refrigerators were not just teeming with potential killers, and now we can all read our scary “hiding right in your cupboard!”-style headlines on Facebook or Twitter instead.

Even though those ’80s news threats were mostly imagined, there are some legitimate “hidden killers” when it comes to email marketing. For senders, one of the biggest potential minefields comes when you decide to send to an old list of email addresses. It’s probably happened to you: someone from another team (or a superior on your own team) brings you a list of addresses that is clearly outdated. They were acquired sometime during the Clinton administration, last mailed 2 years ago (or was it 3?), and probably haven’t been updated…ever. They gave you permission to send all those years ago, so sending to them now is no problem. You’ll remove the hard bounces, then you’re left with a good list of opted-in contacts just waiting to boost your sales numbers. Sounds like a win-win, right?

Not so fast. Even if you received permission to email these contacts, if it happened very long ago there are a number of reasons that permission may not matter. The address may have been abandoned, deactivated, reallocated to a new user, or even repurposed as a spam trap. Let’s look at each of these scenarios and how they can wreak havoc on your sender reputation.

Abandoned addresses

Email addresses, though personal, are a somewhat disposable commodity. With workers switching jobs more than ever, and freemail services providing a myriad of email address options, it’s not uncommon for a recipient to simply abandon an email address. The address remains active and accepts mail, but the user rarely if ever accesses the mailbox.

Most mailbox providers, as we’ve previously discussed, rely heavily on engagement metrics to filter mail. Senders who see good engagement rates from their recipients are more likely to reach the inbox. What you may not know is that many of these providers also look at how many “zombie” mailboxes you send to regularly. If you are frequently mailing to recipients who rarely if ever check their mail, that can have a negative impact on your delivery rates.

Deactivated addresses

This one tends to be the easiest to see: when you send to an address, the message is bounced and you receive a rejection response. Many senders simply gloss over this point because their ESP automatically suppresses bounces, so they know they won’t be mailing to them again. But even a single send to a large number of invalid addresses can cause delivery issues. Once you’ve damaged your sending reputation, the time and effort required to repair it are often much more than would have been required to ensure the list was clean before sending.

Reallocated addresses

If you haven’t mailed to an address in months or years, it’s possible the address was abandoned or surrendered by the previous owner and now belongs to someone else. If this is the case, that recipient hasn’t provided you permission so any mail you send to them is technically unsolicited. These recipients are much more likely to mark your message as spam or report it to a blacklist or spam filter provider.

This scenario is most likely if you haven’t mailed a recipient in well over a year: most webmail providers keep an address active for a minimum of 6 months before it is deactivated, and it’s not uncommon to see another 6 months or more lapse before the address is reassigned to a new user. If the address belongs to a corporate domain, though, the turnover time is often faster.

Spam trap addresses

Of all the problematic addresses, these have the potential to cause the most damage to your reputation and sending ability. Abandoned addresses (and sometimes entire domains) are brought back to life to serve as spam traps, either for the domain owner or a third-party provider like Spamhaus. These trap admins monitor all mail sent to their traps and take action against senders who are seen to be mailing traps with regularity. (For more on spam traps, check out Deliverability 101: Spam Traps.)

Spam traps are most dangerous because they are inconspicuous. They don’t reject mail or throw any red flags to indicate the address has been repurposed as a trap. If you haven’t sent to an address in more than a year, the potential risk of it being a spam trap is greatly increased. While there’s no hard and fast rule, it’s often said that addresses typically remain dormant for 6 to 12 months before being reactivated as a trap.

As a marketer trying to squeeze all possible value from limited resources, sending to an old list can be quite appealing. That appeal, however, vanishes pretty quickly when that old list causes spam folder placement, an ISP block, or even a major blacklisting – preventing all of your recent, engaged recipients from getting the mail as well.

– BG

Delivery Essentials

Is my ESP lying to me?

Collodi_PinocchioIf you use an email service provider, you most likely have tracking reports that tell you the disposition of each message you send. These reports usually indicate the message falls into the broad categories of “delivered” or “bounced“. While many ESPs use more detailed categories, you just want to see if your email made it to the recipient or not…right?

Of course. So what happens when you send out that nice shiny new email and you get a response rate far lower than what you were expecting? Naturally, you check in with some of your best recipients to make sure they got the message. Your tracking shows delivered, but when you reach out they say they didn’t see the message at all. Not in the inbox. Not in the spam folder. Not even in quarantine…now what?

Why is your ESP telling you the message was delivered when it clearly wasn’t?

To answer this common question, let’s dive a bit deeper into what that “delivered” status really means.

When you hit the Send button at your ESP, your mail server will attempt to hand off your message to the mail servers for each recipient. The initial contact between the sending mail server (your ESP) and the receiving mail server (your recipient’s email provider) is often referred to as the “handshake.”

At the time of this handshake, the ESP server will attempt to hand off the message to the receiving server. When this happens, there are a few potential outcomes:

  1. The receiving mail server rejects the message due to the address not existing, the sender being blocked, or other errors considered permanent. These are hard bounces, and usually the receiving server returns a code in the format 5xy, where x and y are additional digits that indicate the specific type of hard bounce. This error typically causes a bounced status in your ESP reporting.
  2. The receiving mail server returns a temporary bounce or deferral. These bounces indicate the mail cannot be delivered at this time, but the sending server should try again later. These are soft bounces, and are typically accompanied by a 4xy error code. These can generate a bounced status in your ESP reporting if the subsequent delivery attempts are not successful. If the later sends do make it through, these will show as delivered. 
  3. The receiving mail server accepts the message for delivery. This is considered a successful delivery, and is accompanied by the code 250 OK. These are reported by your ESP as delivered. 

Once this handoff takes place, the sending server (your ESP) has no further visibility into the delivery of the message. There could be additional spam filters in place after the message is accepted, or individual user settings could cause the message not to be delivered, with no further notification to the sender.

While it’s not extremely common, even major ISPs have been known to have messages “dropped on the floor” if the sender’s reputation is not up to their standards. This is the (highly technical) term for a message that is accepted by the receiving server, but then essentially disappears. It’s not returned to the sender, but it’s also not delivered to the recipient’s inbox or spam folder. It’s simply deleted.

So how do you find out what really happened?

That can be the tricky part. Since the information is not shared with the sender or ESP, the only way to find out for sure what happened to one of these messages is to check the mail logs for the receiving server. In most cases, this will require working with IT staff on the recipient’s side who can search for the message(s) in question and provide a definitive answer on what happened to the message and why.

If the recipient’s IT team isn’t an option, you can also check the content of your message, as well as the reputation of your domain and the domains of any links within the message body. In many cases the initial handoff looks primarily at the reputation of the mail server (IP address), while the subsequent filters can include message content, link URLs, domain reputation, and other factors.

Check out the Resources page for links to some of the most popular reputation tools, and feel free to comment with any additional questions.

– BG