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?

Related Posts

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.

Read More

Holiday mailing advice from mailbox providers

Christine Borgia has a post on the Return Path blog where she interviews a number of different groups (spamfilters, DNSBLs, mailbox providers) about their filtering strategy for the holidays. Overall, no one changes their filtering during the Holiday Mailing Season. On the other hand, many marketers do change their marketing strategies in ways that trigger more filtering and blocking.
The take home message? Pay attention to what is being sent and who it is being sent to. This is nothing new, but many marketers seem to forget it in the effort to get into their customers’ inboxes.

Read More

Content based filtering

Content filtering is often hard to explain to people, and I’m not sure I’ve yet come up with a good way to explain it.
A lot of people think content reputation is about specific words in the message. The traditional content explanation is that words like “Free” or too many exclamation points in the subject line are bad and will be filtered. But it’s not the words that are the issue it’s that the words are often found in spam. These days filters are a lot smarter than to just look at individual words, they look at the overall context of the message.
ISP_tolerances
Even when we’re talking content filters, the content is just a way to identify mail that might cause problems. Those problems are evaluated the same way IP reputation is measured: complaints, engagement, bad addresses. But there’s a lot more to content filtering than just the engagement piece. What else is part of content evaluation?

Read More