A number of people, both at ESPs and on the mailops mailing list, are reporting problems at Hotmail. The most common reports are senders getting
Site hotmail.com (65.55.92.152) said in
response to MAIL FROM (452 Out of memory)
during the SMTP session.
There isn’t much senders can do about this. Hotmail is going to have to fix their resource issue. This may be limited to certain mail clusters, so watching the IP addresses reporting this error and avoiding them may help.
I’ve been seeing a lot of discussion on various fora recently about increased delivery issues at Hotmail. Some senders are seeing more deferrals, some senders are seeing more mail in the bulk folder. Some senders aren’t seeing any changes.
This leads me to believe that Hotmail made some adjustments to their filtering recently. Given some senders are unaffected, this appears to be a threshold change or a calculation change, tightening up their standards. The changes have been around for long enough now it does look like the filtering is working as intended and Hotmail is not going to roll these changes back.
So what can you do to fix delivery of mail that was good enough at Hotmail a few weeks ago and now isn’t?
I’ve heard a lot of marketers complaining about people like me who advocate actually purging addresses from marketing lists if those addresses are non-responsive over a long period of time. They have any number of reasons this advice is poor. Some of them can even demonstrate that they get significant revenue from mailing folks who haven’t opened an email in years.
They also point out that there isn’t a clear delivery hit to leaving those abandoned addresses on their list. It’s not like bounces or complaints. There isn’t a clear way to measure the dead addresses and even if you could there aren’t clear threshold guidelines published by the ISPs.
Nevertheless, I am seeing more and more data that convinces me the ISPs do care about companies sending mail that users never open or never read or never do anything with.
The most recent confirmation was the announcement that Hotmail was deploying more tools to help users manage “greymail.” I briefly mentioned the announcement last week. Hotmail has their own blog post up about the changes.
It seems my initial claim that these changes this won’t affect delivery may have been premature. In fact, these changes are all about making it easier for Hotmail users to deal with the onslaught of legitimate but unwanted mail.
Microsoft announced a number of changes to the Hotmail interface today. It doesn’t look like this will affect how mail is received, but will affect how users can interact with it.
As always, the best advice I can give you is send mail people want and like.