The Weekend Effect

Sending mail only Monday through Friday can cause reputation and delivery problems at some ISPs, even when senders are doing everything right. This “weekend effect” is a consequence of how ISPs measure reputation over time.
Most ISPs calculating complaint rate use a simple calculation. They measure how many “this is spam” clicks a source IP generates in a 24 hour period. Then they divide that number by how many emails were delivered to the inbox in the same 24 hour period.
The weekend effect happens when a sender sends on weekdays and not on the weekend thus lowering the number of emails delivered to the to the inbox. Recipients, however, still read mail on the weekend, and they still hit the “this is spam” button on the email. Even if the number of “this is spam” clicks is lower than a normal weekday, with no incoming email the rate of spam complaints goes above ISP thresholds. Even a very well run mailing program may see spikes in complaint rate on the weekends.
Now, when the ISPs are measuring complaint rates over time, they take the average of the average complaint rates. If the rates spike high enough on the weekend (and they can spike to the 1 – 3% range, even for a well run list), that can hurt the senders’ reputation.
The good news is that ISPs are aware of the weekend effect and take this into account when manually looking at complaints. The bad news is that not all of the major ISPs take this into account when programatically calculating reputation.
There isn’t very much senders can do to combat the weekend effect, except be aware this can happen and may be responsible for poor mailing performances on Monday. If you are seeing delivery problems you think may be a result of the weekend effect you can contact the ISPs and ask for manual review of your reputation. Some ISPs can provide manual mitigation for senders with otherwise clean stats. d

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Yesterday, I posted about reputation as a combination of measurable statistics, like bounce rates and complaint rates and spamtrap hits. But some mailers who meet those reputation numbers are still seeing some delivery problems. When they ask places, like AOL, why their mail is being put into the bulk folder or blocked they are told that the issue is their reputation. This leads to confusion on the part of those senders because, to them, their reputation is fine. Their numbers are exactly where they were a few weeks ago when their delivery was fine.
What appears to have changed is how reputation is being calculated. AOL has actually been hinting for a while that they are looking at reputation, and even published a best practices document back in April. Based on what people are saying some of that change has started to become sender visible.
We know that AOL and other ISPs look at engagement, and that they can actually measure engagement a lot more accurately than sender can. Senders rely on clicks and image loading to determine if a user opened an email. ISPs, particularly those who manage the email interface, can measure the user actively opening the email.
We also know that ISPs measure clicks. Not just “this is spam” or “this is not spam” clicks in the interface, but they know when a link in an email has been clicked as well.
I expect that both these measures are now a more formal and important part of the AOL reputation magic.
In addition to the clicks, I would speculate that AOL is now also looking at the number of dead addresses on a list. It is even possible they are doing something tricky like looking at the number of people who have a particular from address in their address book.
All ISPs know what percentage of a list is delivered to inactive accounts. After a long enough period of time of inactivity, mail to those accounts will be rejected. However for some period of time the accounts will be accepting mail. Sending a lot of mail to a lot of dead accounts is a sign of a mailer who is not paying attention to recipient engagement.
All ISPs with bulk folders have to know how many people have the from address in their address book. Otherwise, the mail would get delivered incorrectly. In this way, ISPs can monitor the “generic” recipient’s view of the email. Think of it as a similar to hitting the “this is not spam” button preemptively.
This change in reputation at the ISPs is going to force senders to change how they think of reputation, too. No longer is reputation all about complaints, it is about sending engaging and relevant email. The ISPs are now measuring engagement. They are measuring relevancy. They are measuring better than many senders are.
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