Case Study: Avoiding Spam Filters. Simple Fixes for Your Emails

This post demonstrates a real-world example of getting caught in the spam filters and how to get out of them.

I recently signed up for Twimailer. Some of their notices are coming in marked as spam and some are not so I thought I’d help them out by figuring out why and sending them an email. (I can’t get in touch with them so someone let them know if you know┬áthe guys.)

Here’s the issue about email and spam. Emails accumulate a +/- score depending if you do things right or wrong. If you include a copyright and use clean html code, you get + marks. Use bad code or break one of a million rules that a sys admin dreamed up and you get – marks.

It’s not easy to dot all your I’s and cross all your T’s. This short example is great example of why you should do everything you can to fix the elements within your control and put the odds in your favor. That way the impact of the elements out of your control don’t affect you as badly.

The first thing I did was review the body of the emails. They include previous tweets. Great idea but some of the tweets are from the distant past and the email got dinged for having an old date in it.

Next I looked at the email headers. In Outlook, open an email and click on View then Options in the menu. This is what you get (mouseover for full size):

This is a screen shot of two email headers. The one on the left is marked as spam and the other one isn’t.

This all seems techy but let me break it down for you so you can understand it yourself. And I don’t make a career out of studying spam engine speak so I’m interpreting these based on my years of experience. I’m not looking these up…

BTW – My mail server uses SpamAssassin. These codes are SpamAssassin’s terminology. Yours are probably different.

Here’s the SpamAssassin Wiki if you want to learn more:

Determined to be SPAM:
X-Mail-Filter-Gateway-SpamDetectionEngine: SPAM,

Spam score (bad thing):
MailFilterGateway Engine (Score=4.451, Score Required 3,

Not listed as a spammer (good thing):
autolearn=disabled, CTASD_SPAM_UNKNOWN -1.00,

Dated in the past (bad thing):
DATE_IN_PAST_12_24 1.77,

HTML message (not bad or good):

Did not use proper html code <html> missing (bad thing):

Content type issue – not sure (bad thing):

Only sent html email vs. mutli-part MIME format (html and plain text) (bad thing):

Domain authentication not setup properly? (bad thing):

Ultimately got a 4 star rating:
X-Mail-Filter-Gateway-SpamScore: ****

What are the biggest offenders? The basics…

Bad HTML coding i.e. invalid HTML

They didn’t include a plain text version (multi-part MIME format)

A pretty big ding for including a date in the past (just include recent tweets vs. mixing in old ones…)

In this screen shot to the left you’ll see there are no <HTML> <body> or <meta http-equiv=”Content-Type” > tags. They only included <div> tags.

The developer who created the email probably didn’t know about these rules and it’s costing the sender its email reputation.

See my recent post about How to Manage Your Email Reputation.

Here are the Top 10 Tips to Improve Email Deliverability and Response.

Posted: March 17th, 2010
at 10:22am by Rob Van Slyke

Tagged with , ,

Categories: Email Critiques,Email Deliverability,Email Optimization

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