Did the algorithm change?

When faced with unexplained deliverability changes one of the first questions many folks ask is “Did the algorithm change.” In many ways this is an meaningless question. Why? Because there are two obvious answers to the question.
A1: Of course it didn’t.
A2: Of course it did.
Both answers are correct, but they’re answering different underlying questions. When we understand how two diametrically opposed answers are both correct, we understand much more about filtering.

What is an algorithm?

When we’re talking about spam filtering the algorithm is the process or rules to follow.

Basically, an algorithm is a computer program that is set up to filter spam to the bulk folder and filter wanted mail into the inbox.  This algorithm doesn’t change. It can’t.
In the case of many (most?) spam filters, the filters incorporate features of machine learning. 
This means the algorithm is constantly changing, learning more and more about what is spam and what is wanted mail based on user interactions.

Algorithms don’t change

Overall, the algorithms don’t change that frequently. They are fed data (lots of data) on a continual basis. They take feedback from recipients (spam / not spam buttons) and developers (new data sets of known bad and known good mail) to learn what good mail looks like and what bad mail looks like. But the underlying code doesn’t change very frequently.

Results change

Machine learning algorithms are only as good as the data they’re fed. In the case of spam filters, the input data is constantly changing. So the output results change. Sometimes an email that was not-spam one day is spam the next because the algorithm caught up with a new threat or new behavior. 

Delivery is still in your control

This machine learning and reliance on end users to help tune filters may make it seem like spam filtering is completely out of the senders’ control. That there is nothing a sender can do to get into or out of the bulk folder. The good news is, the underlying algorithms are pretty simple: wanted mail goes to the inbox, unwanted mail goes to the bulk folder. As with everything, details matter. Senders who are focused on recipients usually don’t have a difficult time reaching the inbox. Companies that focus on themselves and try gimmicks find it much harder to consistently reach the inbox.
 

Related Posts

Doing email right

Over on the MarketingLand website, Len Shneyder talks about 3 companies (Uber, REI and eBay) that do email right. In there he shows how the companies use email to further their business goals while understanding and meeting the needs of their customers.
Meeting the needs of recipients is the way to get your mail to the inbox. Send email that your users want, and they will tell the ISPs when they don’t get your mail. It’s sometimes hard to convince senders of this. Instead they want to tweak URLs or authentication or IPs or domains. But none of those things are what deliverability is all about. Deliverability is about the recipient. Deliverability is about the relationship between the sender and recipient.
Send to the right people – and the right people are those who have asked for and want your mail – and deliverability problems don’t materialize. Sure, every once in a while something might happen that throws mail into the bulk folder for one reason or another. But fighting to get to the inbox isn’t an every day thing. Instead, senders can focus on knowing their users and sending mail that makes them happy when it shows up in the inbox.
 

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Inbox rates and conversion rates

Jeanne Jennings published an interesting bit of research on open rates and inbox rates at ClickZ recently. Essentially she looked at two different industry studies and compared their results.
The first study was the Return Path Global Delivery Survey and the second was the Epsilon North American Trend Results. What Jeanne found is that while Return Path shows a decrease in inbox placement, Epsilon is seeing an increase in average open rate.

There are any number of reasons this could be happening, including simply different ways the numbers are calculated. I am not sure it’s just a numbers issue, though. Many of Epsilon’s clients are very big companies with a very experienced marketing team. The Return Path data is across their whole user base, which is a much broader range of marketers at different levels of sophistication.
I expect that the Epsilon data is a subset of the Return Path data, and a subset at the high end at that. It does hint, though, that when the inbox is less cluttered, recipients are more likely to open the commercial mail that does get in there.

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Spam is not a moral judgement

Mention an email is spam to some senders and watch them dance around trying to explain all the ways they aren’t spammers. At some point, calling an email spam seems to have gone from a statement of fact into some sort of moral judgement on the sender. But calling an email spam is not a moral judgement. It’s just a statement of what a particular recipient thinks of an email.
There are lots of reasons mail can be blocked and not all those reasons are spam related. Sometimes it’s a policy based rejection. Mailbox providers publishing a DMARC record with a reject policy caused a lot of mail to bounce, but none of that was because that user (or that mailing list) was sending spam. Most cable companies prohibit customers from running mail servers on their cable connection and mail from those companies is widely rejected, but that doesn’t mean the mail is spam.
Sometimes a block is because some of the mail is being sent to people who didn’t ask for it or are complaining about it. This doesn’t make the sender a bad person. It doesn’t make the sending company bad. It just means that there is some issue with a part of the marketing program that need to be addressed.
The biggest problem I see is some senders get so invested in convincing receivers, delivery experts and filtering companies that they’re not spammers, that they miss actually fixing the problem. They are so worried that someone might think they’re spammers, they don’t actually listen to what’s being said by the blocking organization, or by their ISP or by their ESP.
Calling email spam isn’t a moral judgement. But, if too many people call a particular email spam, it’s going to be challenging to get that mail to the inbox. Instead of arguing with those people, and the filters that listen to them, a better use of time and energy is fixing the reasons people aren’t liking your email.

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