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March 18, 2010

By Len Shneyder


Images, Paths & Spam Filtering

Reposted from Pivotal IQ Blog

At one time or other we've all asked that age old question what's in a name? Well it's not an old age any more, it's the 21st century and the question to ask today is "what's in a path?" In a word, everything. In a few more words, the final destination of your email.

To borrow a little Jack Lalanne here, content is king and architecture is queen but together you have the entire kingdom, or more importantly the inbox. We know for a fact that content and spam filters take a close look at your p's and q's to determine if the message in your email is fit for general consumption. We know that every element in your message contributes to the overall likelihood of your email being filtered to the inbox vs. the spam folder. However I want to look at one specific component of your email's content that may not get the attention it should: the image path and URL.

An image path is simply a pointer to where the image lives out on the internet. Email marketing is sent without any attachments so the images that are rendered in the customer's inbox are by way of image paths or URLs to the images. Easy enough, this has been the way it's done since like forever, or at least 1999. But from to time I've been seeing people forget that the actual link itself is as important as the image it leads to. Let me give you an example:

<img src="http://www.foo.com/images/banners/image.jpg">  >>> What's the problem with this image link?

If you said nothing you're wrong. There is a problem, it's the word banner. ISP filters and other technology deployed across the internet such as Spamassassin or Privoxy, have complicated rule sets designed to block banners, advertising and all other manner of communication deemed to be UCE (unsolicited commercial email). By naming the folder that contains your image "banner" you are increasing the likelihood that your image, if not your entire email will be outright blocked because you've declared it as a banner in so far as a spam filter is concerned.

The idea here is to have intelligent and easy to read paths that don't attempt to obfuscate what's in them, but also take into account the imperfect nature of filtering technology. Avoid using the word banner or variations thereof, in an image path, or for that matter "ad(s)'.

The problems don't stop here, no the rabbit hole goes much deeper. We live in a fast paced world defined, at times, by 140 characters. Our lives move too quickly for war & peace, unless it can be squeezed in between 60 minutes and grey's anatomy, so we short-hand a lot of stuff including paths in our URLs, such as this:

<a href="http://www.foo.com/mar/mktgspcl/index.html">

Yes, it's March and you have a marketing special ad that you want to link to from your email. Ok, so why didn't you say so? Sometimes it pays to include the vowels if for no other reason than to avoid triggering Spamassassin's consonant filter that eagerly checks for any string of consonants with no vowels greater than 7 characters. By the way, the 7 character length is configurable to be 6 or 5 or anything the operator wants it to be. The net-net here is that although the internet is full of gibberish behind the scenes using plain English doesn't hurt once in a while.

One last thing to keep in mind, image paths, or URL paths for that matter, you should always make folder more than 2 characters. There are specific rules that look for 2 character paths, and 3 character paths at times, so an image folder called /img/ or /im/ should be named /image/ to avoid potential unpleasantries.

I know what's on your mind right now, "will any of this truly condemn me to the spam folder?" Any of this? Hm, possibly not any of this, but in conjunction with the 800 number in your email footer, the dollar signs in your subject line, well you get the picture. To quote Depeche Mode "everything counts in large amounts." Take control of your content and steer the ship to where it needs to go. These are pretty simple things to avoid and once you get the hang of it, you'll find you worry less and sleep more. Cheers!

-Len Shneyder
Director of Deliverability & Messaging
Pivotal Veracity
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In you example:

you really don't need the www. in front.

and you don't need the index.html at the end.

and while we're at it, why not alias the image directory ... /htmldocs/images/... to a host name?

Of course we could also use REGEX to alias a number of hosts to seperate files in the images directory too:


Food for thought.

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