Avoiding Friendly Fire in the War on Spam

As spam continues to overwhelm end-users, spam filters are becoming more and more stringent.

At the same time user's emails seem to be including more and more "stuff" in them that makes them look like spam.

The result is inevitable: more email is becoming collateral damage in the war in spam.

This problem plagues nearly all filters to some extent. When the filter resides server side, users may not even know about missing emails. Often users aren't aware that Outlook or Thunderbird is quietly relocating wanted messages into their "Junk Mail Folders."

The good news is that the causes behind "false-positives" are well understood. By avoiding certain kinds of content - you can feel considerably more confident that your email is actually getting delivered and read.

Images
Any image in an email is prone to make it look more like spam. This includes attached images, or images hosted on a web server. GIF files are more likely to set off alarms than other image formats. In general, the larger the image, the more likely it is to be blocked. This includes background images, images in signatures and especially images that are themselves links to websites.

Links
Obviously, avoiding all links isn't practical - but some kinds are more problematic than others. Especially to be avoided:

Excess HTML
Tables, multiple font-sizes and other extensive formatting can cause email filters to inadvertently trigger. The safest way to author a message is to avoid all HTML formatting and simply use plain-text.

Signatures
People like to create fancy little signatures that look like business cards. They often include images, tables and other HTML formatting. They are prone to get a message deleted for all of the previously mentioned reasons.

Legal Warnings
Legal warnings often mention that a message is "copyrighted" and contains excessive "self reference" back to the email's content. These notices tend to look similar to disclaimers from spammers trying to explain how and why their message isn't actually spam.

Spammy References
I see more and more blocked messages like the following:

From: jojo@jojo.com
To: allmyfriends@variousdomains.com
Subject: Party Tonight!

I don't mean to spam all you people (it's not like I'm offering "special deals on "v1agra" or anything!)

I just want to let you know about the party tonight...

Spam busters can't take a joke. Don't make references to male-enhancement products or imitation Rolex watches. Your email will be blocked.

Advertising added by free email accounts
When Yahoo! or Hotmail adds advertising to your free email account - it makes it look more like spam. Using a free email account makes it more likely for your messages to be blocked.

Anything added by a third-party software product
There are a growing number of products available which have "free" versions. In reality, they are paid by turning each message you send into an advertisement for the product. Each message you send contains a link back to their website and promotional language. This looks like spam.

Some of these products have the underlying purpose of adding "stuff" like animated smiling yellow blobs and dancing pandas to email.

These products include Incredimail and Hotbar. Please, please do not use them.

Ironically, some anti-spam software now employs this marketing tactic. I don't think this approach to marketing is necessarily unethical assuming the user is fully consenting. However, that an anti-spam product might cause the user's own messages to be blocked is somewhat ironic.

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