20% of email doesn't make it to the inbox

Return Path released their global delivery report for the second half of 2009. To put together the report, they look at mail delivery to the Mailbox Monitor accounts at 131 different ISPs for 600,000+ sends. In the US, 20% of the email sent by Mailbox Monitor customers to Return Path seed accounts doesn’t make it to the inbox. In fact, 16% of the email just disappears.
I’ve blogged in the past about previous Return Path deliverability studies. The recommendations and comments in those previous posts still apply. Senders must pay attention to engagement, permission, complaints and other policy issues. But none of those things really explain why email is missing.
Why is so much mail disappearing? It doesn’t match with the philosophy of the ISPs. Most ISPs do their best to deliver email that they accept and I don’t really expect that ISPs are starting to hard block so many Return Path customers in the middle of a send. The real clue came looking at the Yahoo numbers. Yahoo is one of those ISPs that does not delete mail they have accepted, but does slow down senders. Other ISPs are following Yahoo’s lead and using temporary failures as a way to regulate and limit email sent by senders with poor to inadequate reputations. They aren’t blocking the senders outright, but they are issuing lots of 4xx “come back later” messages.
What is supposed to happen when an ISP issues a 4xx message during the SMTP transaction is that email should be queued and retried. Modern bulk MTAs (MessageSystems, Port25, Strongmail) allow senders to fine tune bounce handling, and designate how many times an email is retried, even allowing no retries on a temporary failure.
What if the missing mail is a result of senders aggressively handling 4xx messages? Some of the companies I’ve consulted for delete email addresses from mailing lists after 2 or 3 4xx responses. Other companies only retry for 12 – 24 hours and then the email is treated as hard bounced.
Return Path is reporting this as a delivery failure, and the tone of discussion I’m seeing seems to be blaming ISPs for overly aggressive spamfiltering. I don’t really think it’s entirely an ISP problem, though. I think it is indicative of poor practices on the part of senders. Not just the obvious permission and engagement issues that many senders deal with, but also poor policy on handling bounces. Perhaps the policy is fine, but the implementation doesn’t reflect the stated policy. Maybe they’re relying on defaults from their MTA vendor.
In any case, this is yet another example of how senders are in control of their delivery problems. Better bounce handling for temporary failures would lower the amount of email that never makes it to the ISP. This isn’t sufficient for 100% inbox placement, but if the email is never handed off to the ISP it is impossible for that email to make it to the inbox.

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Delivery emergencies

There is no such thing as a delivery emergency. They just do not happen.
Delivery is fluid, delivery is changing, delivery is complex.
But when delivery goes bad it is not an emergency. There is no need to call up an ISP person at home on a Saturday afternoon and ask them to remove the filters. (And, BTW, experience indicates if you do this that you may have future delivery issues at that ISP.)
I’m sure that people will provide me with examples of delivery emergencies. And, in some cases I might even concede that the receivers will be happy to receive email immediately when it was sent. However, email as a protocol was designed for store and forward. It was not designed to transmit messages instantaneously from sender to receiver. Sure, it works that way much of the time these days. On the whole the Internet is fairly reliable and major servers are connected 24/7 (which wasn’t always the case).
Among many people, particularly recipients and ISP employees, there isn’t the expectation that bulk email is instantaneous. This leads to the belief that delivery problems are not an emergency. Everyone faces them, they get dealt with, life goes on. Demanding an escalation to deal with a “delivery emergency” may backfire and slow down how long it takes to get a response from an ISP.

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E-Postage Just Won't Die

E-Postage is back! Wired covers a report from New Scientist. Here’s what they have to say: “Yahoo’s researchers want you to voluntarily slap a one-cent stamp on your outgoing e-mails, with proceeds going to charity, in a bid to cut down on spam. Can doing good really do away with spam, which consumes 33 terawatt hours of electricity every year, not to mention way too much of our time?”
Alex Rubin at Return Path says hold up, wait a minute. He writes: “Our contacts at Yahoo! tell us this idea is purely in the research realm, and is not scheduled for development in Yahoo! Mail. In other words: it isn’t even vaporware and isn’t likely to be a part of the Yahoo! mail system anytime soon.” He goes on to say (I’m paraphrasing) that oops, Yahoo didn’t really intend for this research to become public.
So, apparently, there are no plans for Yahoo to roll out E-Postage today, tomorrow or next week. Nothing to see here, beyond a simple web site and some thoughts from a Yahoo researcher. Some individual’s hopeful vision for the future, not a corporate announcement of an upcoming product.
E-Postage has always been a neat idea, I’ve thought. A neat idea beset by insurmountable problems. First, end users don’t want to pay for the email messages they send, they want all you can eat. With years of webmail providers offering free email access, you’ll have a heck of a time convincing somebody’s grandmother that they have to pony up a nickel to be able to email the grandkids.
Then, answer me this: Who’s going to handle the economics on the back-end? And any time you have a computer storing a resource (like, say, account information for that tiny little bit of money you’ll need to be able to send me an email), that information can be hacked, exploited, stolen. You think spammers are actually going to pony up? Why would they? They’ll just hack into millions of exploitable computers, stealing five cents from everyone along the way, and gleefully shoveling millions of spams into millions of inboxes.
This concept of E-Postage, either paying money to send email, or spending “computational power” to send email, has been kicking around for years. Periodically, some researcher comes up with the idea anew, and suggests that we all immediately adopt their sure fire plan to solve the world’s spam problem, immediately, pennies at a time. These ideas never seem to go anywhere. And that will never change until somebody can actually convince most of the world to adopt their proposed scheme. Will it ever happen? Never say never, but I have no plans to rush out and buy e-Stamps any time soon.
— Al Iverson

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The delivery communication gap

There seems to be a general uptick in the number of specific questions that ESPs and commercial senders are asking recently. I’m getting them from clients, and I’m hearing similar stories from my various contacts over on the ISP side. The questions cover a wide range of areas in email delivery, but the underlying issue is really that there are no real fixed rules about email delivery anymore. The only rule is “send mail users want to receive” and there are no specific guidelines to how to do that.
This is frustrating for a lot of people. They want to know exactly how many complaints they need to stay under. They want to know what “engagement” means and how exactly the ISPs are measuring it. They want to know all of the metrics they need to meet in order to get mail to the inbox.
There is a lot of frustration among senders because they’re not getting the answers they think they need and they feel like the ISPs aren’t listening to them.
Likewise there is a lot of frustration among ISPs because they’re giving answers but they feel like they’re not being heard.
Some of the problem is truly a language difference. A lot of delivery people on the ESP side are marketers first and technologists second. They don’t have operational experience. They don’t have that any feel for the technology behind email and can’t map different failure modes onto their causes. Some of them don’t have any idea how email works under the covers. Likewise, a lot of postmaster people are technologists. They deeply understand their customers and their email servers and don’t speak marketing.
The other issue is the necessary secrecy. Postmasters have been burned in the past and so they have to be vague about what variables they are measuring and how they are weighting them.
All of this leads to a very adversarial environment.
I’ve been talking with a lot of people about this and none of us have any real answers to the solution. Senders say the ISPs should spend more time explaining to the senders what they need to do. ISPs say the senders should stop sending spam.
Am I quite off base here? Is there no communication gap? Am I just cynical and missing some obvious solution? Anyone have any suggestions on how to solve the issue?

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