Do we take email reliability/deliverability for granted? I’m talking about email that traverses the Internet (e.g. outside of internal corporate email delivery, which there should be no question about reliability).

It seems to me that I’ve had an increase in the number of complaints/reports from some of my clients about lost emails in the past 6 months. In some cases, it was emails that they sent friends or customers that never arrived. In other cases, it was mail that was sent to them that they never received. Some of my clients were particularly distressed because the lost messages were to (or from) customers of their own.

In some cases, there were non-delivery receipts (NDRs, or “bounce messages“), but in many cases, the message simply never made it, and there was no NDR sent back. NDRs can sometimes provide a breadcrumb of a clue as to the reason for the delivery failure (but not always).

These days, once your email leaves your ISP or email provider’s outgoing server, it has to run a gauntlet of sorts. There are so many anti-spam measures out there — at so many different levels — that I’m not surprised by the phenomenon of lost emails.

First, ISPs and email providers of all stripes have instituted various Anti-Spam measures. Some of these can be tweaked by end users (white lists, spam sensitivity, spam filtering on/off), others are more rigid and are controlled at the infrastructure and server level by administrators. Then you have anti-spam measures at the endpoint, typically anti-spam features built in to a given email client (e.g. Outlook, Outlook Express, OS X Mail.app) and sometimes Junk Mail software that’s part of a security software suite.

I’m sure I’ve left out other elements of the virtual gauntlet, but you get my point. Spammers have created such a backlash of countermeasures, that there is always going to be some percentage of legitimate email that gets caught in the dragnet. By legitimate, I mean email that there is no question that the recipient wants to get. I know the definition of legit email can be very much an “eye of the beholder” thing, but that’s a topic for another discussion.

In each of the cases I dealt with, I made sure to remind my clients be familiar with the anti-spam measures and policies that their ISP/email providers had in place as well as to learn the junk mail features of their email client and any security software they may be running. In parallel, they should encourage their clients and friends to do the same. Education and awareness are the key elements. Beyond that, I don’t know much more than can be done.

I still think there is some parallel universe out there — full of lost keys, missing socks, and emails that never made it to their destination.