All filters are not equal

Many questions about delivery problems often assume that there is one standard email filter and the rules are the same across all of them. Unfortunately, this isn’t really the case.

The biggest divide is consumer versus business filters. Business filters don’t really care about things like engagement. A sender could have near perfect engagement with a message to a business. But a decision maker inside the company can still decide that mail doesn’t get in. There’s no appealing to permission or wanted mail. Employee mail is provided for the good of the business, not for the good of the individual user or the sender.

There are other less obvious divides between filters as well.

I frequently refer to “webmail providers” (Oath, Microsoft, Gmail). These are companies that control the mail delivery and, for the bulk of their customers, control the mail client as well. They can use engagement filters because they have more data. Other companies, like broadband providers or web hosting services, don’t have the same level of access to customer behaviour, so they can’t heavily use engagement as part of their filtering processes. They may have some access to IMAP folders, depending on their setup, so they can look at some engagement flags.

Filtering companies also have their own type of filters. In many cases, though, they have no access to any engagement filters. They handle mail at a discrete point that starts during SMTP sessions and ends when the mail is handed off to the local delivery agent. These companies cannot use engagement as part of their filtering process all, they simply don’t have access to that data.

Understanding what data filters act on and what data they have access to can inform how to deal with blocks and delivery problems.

 

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Do system administrators have too much power?

Yesterday, Laura brought a thread from last week to my attention, and the old-school ISP admin and mail geek in me felt the need to jump up and say something in response to Paul’s comment. My text here is all my own, and is based upon personal experience as well as those of my friends. That said, I’m not speaking on their behalf, either. 🙂
I found Paul’s use of the word ‘SysAdmin’ to be a mighty wide (and — in my experience — probably incorrect) brush to be painting with, particularly when referring to operations at ISPs with any significant number of mailboxes. My fundamental opposition to use of the term comes down to this: It’s no longer 1998.
The sort of rogue (or perhaps ‘maverick’) behavior to which you refer absolutely used to be a thing, back when a clean 56k dial-up connection was the stuff of dreams and any ISP that had gone through the trouble to figure out how to get past the 64k user limit in the UNIX password file was considered both large and technically competent. Outside of a few edge cases, I don’t know many system administrators these days who are able to (whether by policy or by access controls) — much less want to — make such unilateral deliverability decisions.
While specialization may be for insects, it’s also inevitable whenever a system grows past a certain point. When I started in the field, there were entire ISPs that were one-man shows (at least on the technical side). This simply doesn’t scale. Eventually, you start breaking things up into departments, then into services, then teams assigned to services, then parts of services assigned to teams, and back up the other side of the mountain, until you end up with a whole department whose job it is to run one component of one service.
For instance, let’s take inbound (just inbound) email. It’s not uncommon for a large ISP to have several technical teams responsible for the processing of mail being sent to their users:

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It depends… no more

The two most hated words in deliverability. Many people ask general questions about deliverability and most experts, including myself, answer, “It depends.”
There are a lot of problems with this answer. The biggest problem is that it’s led to the impression that there are no real answers about deliverability. That because we can’t answer hypothetical questions we are really just making the answers up.
Depositphotos_53649203_original
The reason we use “it depends” is because the minute details matter when it comes to deliverability. Wether or not something will hurt or help deliverability depends on the specific implementation. Who’s doing the sending? What is their authentication setup? What IP are they using? How were the addresses collected? What is their frequency? What MTA is used? Are they linking to outside sites? Are they linking to outside services? Where are images hosted? The relevant questions go on and on and on.
I am going to stop saying it depends when answering generic deliverability questions. Instead I will be using the phrase “details matter.” Details do matter. Details are everything. Details drive deliverability.
Details Matter
The importance of details is why many deliverability people hedge their answers. The details do matter.
I will do my best to stop answering It Depends to deliverability questions. Instead, I’ll be answering with question and pointing out the details matter.
 

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Updating the filtering model

One thing I really like about going to conferences is they’re often one of the few times I get to sit and think about the bigger email picture. Hearing other people talk about their marketing experiences, their email experiences, and their blocking experiences usually triggers big picture style thoughts.
Earlier this week I was at Activate18, hosted by Iterable. The sessions I attended were interesting and insightful. Of course, I went to the deliverability session. While listening to the presentation, I realized my previous model of email filtering needed to be updated.

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