E-Fail - What Good is Email?

Like many other people, I often send my friends email messages with trivial value. They may contain an interesting website or a blog entry.

I often don't hear back from them, and don't expect to. Sometimes, I'll mention the said email in conversation. Usually they received it. On rare occasion, they had not.

The email message could still be in transit. I've seen messages literally take days on a few occasions. This can be due to the receiving mail server being down on the first attempt to send.

In recent times, the most common cause is over-zealous spam fighting systems. Users can check their own spam program for deleted messages, even though they frequently do not. Worse, they commonly don't have any access to messages blocked by their ISP.

You may say to yourself, "I've disabled spam filtering with my ISP." It's more accurate to say that you think you've disable their filtering. Most ISP's employ multiple levels of email analysis. The first tier may block messages from senders using email servers which are listed in any number of blacklists (DNSBLs). The second tier might use a common content processing filter such as SpamAssassin. Users are likely to have control over the later, but not the former.

Blacklists are adapting a more dynamic nature. They are quicker to add and remove offending networks and servers than they have been historically. On one hand, this can increase accuracy on average. On the downside, mostly-legitimate networks might be listed temporarily, resulting in a handful non-offending emails being blocked.

All of this adds up to email being unreliable. One possible approach is the use of return-receipts. Upon the recipient receiving an email, a message is sent to the sender letting them know it arrived successfully. This doesn't really improve deliverability, but it does provide affirming knowledge to the sender. There are a few issues with this approach.

For one, return-receipts commonly load up email with extraneous HTML and images. While this doesn't hurt accuracy, it can set off spam mail stoppers. This further reduces deliverability, however you will accurately know your message was never delivered. Newer versions of Outlook give users the ability to disable image rendering, which causes third-party return-receipt software not to function properly.

Another problem is social in nature. Users don't like the idea that they're being tracked. I sometimes receive email with return-receipts attached to support requests. They go to the back of the queue with messages in ALL-CAPS and marked as high-priority.

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