How can I know that emails I sent were received and opened?

I want to start by making this very clear: there is no reliable way to tell with certainty that an email you send has, or has not, been received, opened or read. None.

If your business relies on that, then you need to be investigating alternative approaches to whatever it is you're communicating.

There are a couple of conceptual reasons for this, and you can choose one or the other depending on your cynicism:

• Email is broken.

• Your recipient's right to privacy trumps your need to know.

We can argue about the first all you want, but it's really that second that says it all.

It's spam that made everyone realize just how important that last one is. It's spam that has led most all email programs to disable by default the mechanisms that could be used to track email receipt.

So you can blame spam, if you like, for making this impossible. Whether that's part of "Email is broken", or "right to privacy", it is what it is, and at the risk of repeating myself it means that you cannot reliably track whether or not a specific email has been opened or read. Period.

The Traditional Methods

There are two traditional methods to track whether or not an email has been received or opened.

Delivery and Read Receipts

The email protocol allows email messages to include a request for a "Delivery Receipt" and/or a "Read Receipt". The idea is that when the message is delivered to the inbox the email program would automatically send a "delivery receipt" email back to the sender saying "it's been delivered". Similarly, when the email is opened the email program would automatically send an "Read Receipt" email back to the sender saying "it's been opened". (Whether someone actually read it is beyond the abilities of computer to know, all they can say is "it was opened and displayed on the screen".)

Here's the problem: most email programs do not respond to delivery or read receipts any more; it's disabled by default. Which means that the requests for these are completely ignored. You'll get no notification at all, even if you ask for one.

The reason is, as you might have guessed, spam. Spammers could use receipts to validate that an email they're sending to is a valid email address, and thus should be spammed even more.

No one wants that, so the feature is completely disabled by default.

Tracking Images or "Bugs"

In HTML or rich-text, images can be included in email messages. Those images can either actually be included with the message, or they can be fetched from some location the internet in order to be displayed. A good example is the Ask Leo! newsletter. It includes at least two images: a logo at the top, and my signature at the bottom. The images themselves are not actually included in the email, but instead are simply references to images stored here on the Ask Leo! web site.

I can tell when those images are referenced. When you open an email with those images, and have image display enabled, your email program makes a request of my web server to fetch those images for display. My web server can log that. In fact, while I don't, it's quite possible to include in that request not only the image desired, but also the email address of the recipient of the message that needs the image.

In other words, it sounds like a perfect tracking mechanism to determine whether an email has been opened or not.

Which is why spammers started doing exactly that; once again to determine that the email address they just sent to is a valid email address with a real person who looks at it, and thus is deserving of more spam.

And that, in turn, is why email programs no longer display images by default.

And if image display is disabled, then the entire approach to tracking using image references fails completely.

For the record: most companies that offer to track email delivery and opens use image references. Since many people do enable image display - typically for people they know and trust - it can still work - sort of. The problem is that there's no way to know whether someone has image display turned off. If they do there's no way to know if they opened your message or not. The technique is simply not 100% reliable. Period.

Alternatives

The most common alternative boils down to a private messaging system.

The technique works like this: you place your message on a on-line service of some sort - perhaps even your own web server, and then email a link to the message instead of the message itself. In order to read your message, the recipient must click on the link and visit the web server holding the message. That visit can be reliably logged.

Exchange Server is another kind of "private messaging system". People on an Exchange Server based system sending to others on that same system can often get reliable notification that email has been read or opened.

Other alternatives involve somehow obfuscating the message such that some other trackable resource on the internet must be involved in order to perhaps decode the message.

But if the email message can simply be read on its own without requiring these additional resources - just by showing up in someone's inbox - there's just no way to know with 100% certainty whether or not the message was delivered, opened or read.