The long tail of domains

I frequently get clients telling me that they have about 15 (20, 30) major domains on their list, and then a long tail of domains with only a couple of recipients. If you sort simply by the left hand side of the @, that’s true.
When you’re sending email, it’s not just the domain in the email address that is important. Of equal importance is the MX. The MX is what actually handles the mail and where many filters are applied. Sorting by MX, instead of simply recipient domain, can identify that most of your small business clients are hosted at a particular provider. The number of subscribers behind that filter may be enough to push that filter into your top 10 or even top 5 recipient domains.
There’s a much smaller tail when grouping recipients by MX domain. It makes it much easier to understand where blocks are happening. I have even seen cases where clients didn’t realize they were blocked at a commercial provider because they only saw the “onesie twosie” domains as undeliverable. They missed a real problem with blocking because they were looking at the wrong data.
I sometimes get the side eye from some ISP folks if I use the term receiver (because, well, they’re senders as much as they are receivers). But I use receiver to help distinguish between the recipient domain and the actual domain handling the email.
When was the last time you looked at your delivery by filter or MX rather than by recipient domain? What did you find?

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Typo traps

People make all sorts of claims about typo traps. One claim that showed up recently was that Spamhaus has just started using typo traps. I asked my Facebook network when people started using typos to detect incoming spam.
Two different colleagues mentioned using typos, both on the left hand side and the right hand side, back in ’98 and ’99.
The point is, typo traps are absolutely nothing new. They are, in fact, as old as spam filtering itself. And as one of trap maintainers remind me, not all of them even look like typos. It’s not as simple as hotmial.com or gmial.com.
I really think that focusing on traps is paying attention to the wrong thing.
The traps are not the issue. The underlying issue is that people are signing up addresses that don’t belong to them. Sometimes those are addresses that are spamtraps. Sometimes those are simply addresses that belong to someone else. Those addresses don’t belong to customers, they belong to random people who may never have heard of the sender. Sending mail to those people is sending spam.
Just trying to remove traps from your address lists isn’t going to solve the underlying problem. Instead, focus on improving your data process to keep from sending mail to random strangers.

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Don't wait to address delivery problems

One of the worst ways to deal with blocking issues is to ignore them and hope your mail magically moves from the bulk folder back into the inbox. While this does happen as ISPs and filter companies update their filters, it’s not that common and it’s usually the result of a sender actually cleaning up their sending processes and improving the quality of the mail they send.
Do not ignore blocks. What I generally tell people is that it takes at least as long to repair a bad reputation as it took to get that bad reputation in the first place. If you wait months before actually addressing delivery problems, you’re not going to make a change and have the filters react in hours.
This doesn’t mean that every block is a business crisis. Blocks happen and they do go up and down based on thresholds and automatic monitoring scripts and content. But if a block happens consistently for 4 or 5 days in a row it is time to look at what you’re doing. Don’t just focus on the sidelines and little stuff, either. Look at your marketing program and the mail you’re sending.

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Ever changing filtering

One of the ongoing challenges sending email, and managing a high volume outbound mail server is dealing with the ongoing changes in filtering. Filters are not static, nor can they be. As ISPs and filtering companies identify new ways to separate out wanted email from unwanted email, spammers find new ways to make their mail look more like wanted mail.
This is one reason traps are useful to filtering companies. With traps there is no discussion about whether or not the mail was requested. No one with any connection to the email address opted in to receive mail. The mail was never requested. While it is possible for trap addresses to get on any list monitoring mail to spam traps is a way to monitor which senders don’t have good practices.
New filtering techniques are always evolving. I mentioned yesterday that Gmail was making filtering changes, and that this was causing a lot of delivery issues for senders. The other major challenge for Gmail is the personalized delivery they are doing. It’s harder and harder for senders to monitor their inbox delivery because almost every inbox is different at Gmail. I’ve seen different delivery in some of my own mailboxes at Gmail.
All of this makes email delivery an ongoing challenge.

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