Knowledge Base - How to avoid spam filters

Subject Line
The subject line is the easiest way to get your email filtered as spam. Even if your email doesn't get filtered as spam, your subject line is how your recipients judge whether or not to open or delete your message, so it's got to be relevant. Here are some tips for crafting your subject line:

  • Write it so that in the blink of an eye, a recipient knows: 1) who sent it, and 2) what it's about.
  • Make it intriguing, but in a way that's relevant to your audience, and that reinforces who sent the message, and what it's about. For instance, if we sent a MailChimp newsletter with the subject line, "FREE WHITEPAPER INSIDE!" we'd be idiots. Something like, "Whitepaper: Advice for improving your newsletter open rates" would be better.
  • Avoid spammy words and phrases, like FREE, mortgage, insurance, act now, casino, limited time, coupons, click now, open immediately, etc.
  • Don't!!! use !!! too!!! much!!! punctuation!!!!!
  • Avoid expletives (this one's a no-brainer)
  • Don't get creative with numbers/characters in place of letters, like: V1AGRA, SW!VEL, H3LL0, etc.


Content of Message
Spam filters look for "spammy" clues both on the surface, and "under the hood" of your email's content:

  • Don't use "spammy" words and phrases (see above) in your content. It's easier than you think to accidentally use spammy words, like "New XXX-Large T-shirts Available" or "Join us for Casino Night!" or, "Click now to download." Put down your "Copywriting that SELLS!!!!" book when you're writing your email newsletters. Many of the call-to-action "tricks" you might have learned in the direct-marketing world will just get you in trouble with spam filters.
  • Don't just send a giant graphic. That's what spammers do. Your HTML email needs a "healthy balance" of graphics and text. If you're just sending a simple invitation, or a simple promotional piece to your recipients, and all it takes is a simple graphic, you can still include text in the footer area, such as your "unsubscribe" link, your physical mailing address, etc.
  • Always include a plain-text alternative with your HTML email. Spammers are lazy, and don't bother to do that. It may seem like a hassle to write both versions of your email, but you really need to include it. Plus, we generate it for you, so no excuses! And don't skimp on the plain-text version either. In the past, we've gotten a little lazy, and made our plain-text alternatives say, "You're viewing this because you can't view HTML email. Visit this URL to view our message in your browser." Nowadays, spam filters compare your plain-text alternative to your HTML email. If 95% of the message is in HTML, and 5% is in plain-text, that looks sloppy and lazy to the spam filters.
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