The Physics of the Email Universe

We talk a lot about rules and best practices in email, but we’re mostly talking about “squishy” rules-of-thumb that are based on simplified models of how mail systems, spam filters, recipients, postmasters and blacklist operators behave. They’re the biology, ecology and sociology of the email ecosystem.
There’s another set of rules we tend to only mention in passing, if at all, though. They’re the steely, sharp-edged laws that control the email universe. They’re the RFCs that define how email works and make sure that mail systems written by hundreds of different people across the globe all work and all interoperate with each other.
Building a message from Zeros and Ones
RFC 5322 – Internet Message Format
This tells you everything you need to know about crafting a simple email, with a subject line, a sender, some recipients and a simple plain-text message. It’s also the foundation of all fancier emails. If you’re creating emails, this is where to start.
A little more than plain ASCII
RFC 2047 – MIME Part 3: Message Header Extensions for Non-ASCII Text
RFC 2047 is one small part of the MIME (Multipurpose Internet Mail Extensions) suite of protocols that allow you to include pictures and attachments and prettily formatted text and comic sans in your email. This part defines how you can put things other than the plainest of plain text in your subject lines or in the “friendly from” of your message. It’s what allows you to put Hiragana, or Cyrillic, or umlauts, or cedillas, or properly matched double quotes in your subject line. It also let’s you put hearts or smiley faces or other little pictograms there – but nothing this useful is going to be perfect.
RFC 2045 – MIME Part 1: Format of Internet Message Bodies
This shows how to send an image, or a plain text mail in a different character set, or an HTML mail. It doesn’t tell you how to send plain text and HTML, or to send HTML with embedded images, or a message with an attached document. For that you need…
Finally, Modern Email
RFC 2046 – MIME Part 2: Media Types
This builds on RFC 2045 to allow you to have many different chunks in a message – this is what you need if you want to send “proper” HTML mail with a plain text alternative, or if you want embedded images or attachments.
Getting From A To B
RFC 5321 – Simple Mail Transfer Protocol
A message isn’t much use unless you send it somewhere. RFC 5321 explains the mysteries of actually sending that message over the wire to the recipient. If you need to know about the different phases of a message delivery, what “4xx” and “5xx” actually mean, why there’s not really any such thing as a hard or soft bounce defined, just temporary or permanent failures, or anything else about actually sending mail or diagnosing mail delivery, this is your starting point.
The Rest Of The Iceberg
I’ve only touched on the very smallest tip of the email iceberg here. There’s much, much more – both in RFCs and ad-hoc non-RFC standards. If you’re interested in more, this is a decent place to start.

Related Posts

Think before you mail

I get quite a bit of unsolicited mail. I mean, sure, we all get a lot of spam, but that’s not the unsolicited mail I’m talking about. I’m talking about from people and companies in the email space. They want to make sure I’ve seen their new whitepaper or article about delivery. Or they have a question about something I’ve written here. Or they are looking to hire me.
All of these things are great. I love hearing from readers, either in comments or in email. We have a valid (unfiltered) contact address here on the blog. My email address(es) aren’t difficult to find. I want to talk to people.
Sometimes some of the people who contact me do actually send spam. It’s bulk, it’s impersonal, it’s not about me or my perspective it’s about them trying to sell something (themselves, their newest product, their company) to anyone who is buying.
If it’s clear it’s a one off I’ll generally just move the mail out of my inbox and forget about it. Sometimes, though, there are hints that this is more than just a one time mail. The email will have an unsubscribe link, or it’s the third or fourth time I’ve gotten mail from that sender or it will be from a PR company. I deal with them in different ways. Sometimes I’ll offer a different email address that I route better, or I’ll just filter the mail based on some unique bit of the header.
The ones that really get me, though, are when the senders argue with me that I should feel special to get their bulk mail. “It was individually sent to you!” “I sent it because you’re such a great resource and wanted to say thank you!” But it was bulk mail, mail dozens of other people got (hint: the email / delivery industry is very small. we talk to each other all the time, if you send mail to more than one of us, we’re going to talk about it).
I have no problem with you inviting me to your event. Or telling me about the latest or greatest thing you wrote. I don’t even mind the occasional one-off bulk mail. But if you are sending mail to a specific person, put in the 20 seconds to personalize it and make it feel like it’s special for me.
A few moments to think and personalize before you send that email will make your recipient much more open to your pitch. This is as applicable to one off mail as it is to bulk.

Read More

Is there really one way to email successfully?

I’ve been watching a bunch of folks discuss someone’s mailing practices. The discussion has been fascinating to me.  I’m hearing from the conversation is that there are very specific rules regarding how every company should mail. And that anyone who deviates from those practices is heading down the path to failure. Doing it wrong.
This theme has come up before, when I’ve heard expert marketers comment that Groupon proved how wrong the “daily email is too much” advice was. My response to that is confusion. Who decided daily email was too frequent and wouldn’t work?
I come from a non-marketing background, so maybe I’m missing some essential bit of wisdom or context. But it strikes me that a lot of the rules (no daily email, never establish aggressive engagement metrics) are really stifling innovation. There seems to me to be an unwillingness to think about why it might work if a particular sender does something against the grain.
Of course, once something has proven a success, everyone jumps on the bandwagon. Half my potential clients over the summer told me they “want[ed] to be the next Groupon.” Most of them didn’t make it, though.
I look at email as having a massively diverse user base. There are lots of people who use email in ways I would never consider. There are lots of people who think the way I use email is wrong. Unlimited opportunities for smart marketers exist.
The more cynical part of my brain says that finding and developing an enthusiastic recipient base takes too much time. Companies want to be the “next groupon” or the “next facebook”. But they want to do it by copying the business model, not by being innovative and meeting some need that currently isn’t being serviced.
There are, of course, some models that are never going to work, like randomly harvesting addresses and sending spam. But I don’t think that means email marketing is dying, just that innovation and imagination might be.

Read More

Email is store and forward

Many of us are so used to email appearing instantaneous, we forget that the underlying protocol was never designed for instant messaging. When the SMTP protocol was originally proposed it was designed to support servers that may have had intermittent connectivity. The protocol allowed for email to be spooled to disk and then sent when resources were available. In fact, almost everyone who was around more than 10 years ago knows of a case where an email took weeks, months or even years to deliver.
These days we’re spoiled. We expect the email we send to friends and relatives to show up in their mailbox within moments of sending it. We expect that sales receipt or e-ticket to show up in our mailbox within instants of a purchase. We expect that our ISPs will get us email immediately, if not sooner.
But there are a lot of things that can slow down email delivery. At several points in the process an email may be spooled to disk. It stays on the spool until the next part of the delivery process can happen. Other points of slowdown include the various anti-spam, anti-virus and anti-phishing protections that ISPs must implement. Then add in the extreme volume of email (around 10 billion messages a day) and all of a sudden email delivery is slower than many senders and recipients expect it to be. This delay is not ideal, but the system is designed so that mail is not silently discarded.
While individual emails may be delayed, most users will rarely see that delay in the email that they send. Bulk senders, who may be sending thousands or hundreds of thousands of emails a day, may see more delays in a single send than the average user sees in years of sending one-to-one email.
Email is store and forward, not instant. Sometimes that means there is a delay in getting email into the recipients inbox. And, sometimes there isn’t anything anyone can do to speed up delivery, except to adjust expectations of how email works.

Read More