How HTML Code Affects E-Mail Deliverability
Have you hugged your e-mail's HTML code lately?
Have you hugged your e-mail's HTML code lately?
A common email marketing misconception is email is filtered because it contains words such as “free” in the subject line or body. By itself, that won’t get your email filtered. Though certain content combinations may get a message filtered, ISPs may be trapping your legitimate email for infractions you rarely pay attention to.
Take HTML code. Using outdated or incorrect code is a major reason why email to domains such as MSN/Hotmail and AOL are blocked or delivered to bulk or junk mail folders.
You may think you don’t have to worry about this. Your email may render correctly and look just fine to you. Wrong! Pivotal Veracity, a delivery-monitoring service provider, estimates nearly 100 percent of all HTML email doesn’t comply with World Wide Web Consortium (W3C) standards.
Because each ISP handles email differently, messages that get past the filters at one destination may be filtered or entirely blocked at another. Why are some ISPs so concerned about HTML code? You can thank spammers, of course. HTML syntax and format errors are common tricks spammers use to foil standard content filters.
Some W3C infractions are minor and won’t cause email to be filtered. An example is not using “alt” tags, which describe the content in an image tag. Many other innocuous-appearing coding errors or tricks may send your email straight to the bulk folder.
Pivotal Veracity recently tested hundreds of HTML email messages to see whether they landed in the inbox or the bulk folder, or were blocked outright. They came up with these surprising results:
http://companyx.com/maintainyourprofile.php
Readers see the second URL in the message, but they’d be sent to the first URL.
AOL’s HTML Validator
While conducting tests for our clients several months ago, we discovered a new AOL email filter that scans incoming messages for HTML syntax and format errors. If it detected invalid HTML, it rejected the message. AOL even created a special bounce code it used when rejecting a message for this reason.
Common errors, such as using “” to close an HTML tag instead of the “,” could trigger the filter. Pivotal Veracity’s recent testing suggests AOL may no longer be applying this filter. The bottom line is check your code carefully and correct any syntax errors.
Minimizing HTML Filtering Problems
How do you minimize or eliminate HTML filtering problems at ISPs? A few suggestions:
In a future column, we’ll walk you through an actual diagnosis of code problems and show you how to resolve them. Stay tuned.
Till then, keep on deliverin’.
Want more email marketing information? ClickZ E-Mail Reference is an archive of all our email columns, organized by topic.