Email Marketing & AutomationMarketing & Sales Videos

Email Subject Line Words That Trigger Spam Filters And Route You To The Junk Folder

Getting your emails routed to the junk folder sucks… especially when you’ve worked so hard to build a list of subscribers that fully opted in and wish to view your email. There are a few factors that impact your sender reputation that can impact your ability to make it to the inbox:

  • Sending from a domain or IP address that has a poor reputation for spam complaints.
  • Getting reported as SPAM by your subscribers.
  • Getting poor interaction from your recipients (never opening, clicking, and immediately unsubscribing or deleting your emails).
  • Whether or not the proper DNS entries can be validated to ensure the email is authorized by the company to be sent by that email provider.
  • Getting a high number of bounces on the emails you send.
  • Whether or not there are insecure links in the body of your email (this includes URLs to images).
  • Whether or not your reply email address is in the mailbox recipient’s contacts, of if they’ve been marked as a safe sender.
  • Words in your email subject line that are common with spammers.
  • Whether or not you have an unsubscribe link in the body of your emails and what you call it. We sometimes advise clients to update this to preferences.
  • The body of your email. Often, a single image HTML email with no text may flag the mailbox provider. Other times, it can be words within the body of your email, the anchor text in links, and other information.

It’s important to note that these algorithms are highly customized by mailbox providers. It’s not a checkmark list that you must meet 100% of the guidelines. As an example, if your reply email address is in the mailbox recipient’s contacts, you’ll almost always find your way to the inbox.

If you have a great inbox placement and tons of engagement on your emails, you can get away with far more aggressive emails and use words that may trigger a sender with a poor or young reputation. The goal here is when you know you’re getting routed to the junk folder, to minimize the words that may flag SPAM filters.

Email Subject Line SPAM Words

If you don’t have a solid reputation and you’re not in the recipient’s contacts, one of the easiest ways to get your emails stuck in the Junk Folder and classified as SPAM is the words you’ve utilized in your email subject line. SpamAssassin is open-source spam blocking that publishes its rules for identifying SPAM on its Wiki.

Here are the rules SpamAssassin utilizes with words in the subject line:

  • The subject line is blank (Thanks Alan!)
  • The subject contains the words alert, response, assistance, proposal, reply, warning, notification, greeting, matter, credited, owe, indebted, debt, obligation or reactivation… or misspellings of those words.
  • The subject line contains the month abbreviated (example: May)
  • The subject line contains the words cialis, levitra, soma, valium or xanax.
  • The subject line begins with “Re: new”
  • The subject line contains “a bigger”
  • The subject line contains “approves you” or “approved”
  • The subject line contains “at no cost”
  • The subject line contains “security measures”
  • The subject line contains “cheap”
  • The subject line contains “low rates”
  • The subject line contains the words “as seen”.
  • The subject line begins with a dollar sign ($) or spammy looking monetary reference.
  • The subject line contains the words “your bills”.
  • The subject line contains the words “your family”.
  • The subject line contains the words “no prescription” or “online pharmaceutical”.
  • The subject line starts with lose, “weight loss”, or talks about losing weight or pounds.
  • The subject line starts with buy or buying.
  • The subject says something bad about teens.
  • The subject line starts with “Do you dream”, “Do you have”, “Do you want”, “Do you love”, etc.
  • The subject line is ALL CAPITALS.
  • The subject line contains the first part of the email address (example: subject contains “Dave” and the email is addressed to
  • The subject line contains sexually-explicit content.
  • The subject line attempts to obfuscate or misspell words. (example: c1alis, x@nax)
  • The subject line contains an English or Japanese UCE code.
  • The subject line contains Korean unsolicited email tag.

In my honest opinion, most of these filters are absolutely ridiculous and often block great email senders from making it to the inbox. Virtually every consumer expects email from the vendors that they’re doing business with, so the fact that saying anything regarding an offer or price may get you blocked is quite frustrating. And what if you actually do want to provide something FREE to a subscriber? Well, don’t write it in a subject line!

Need Help With Your Email Reputation?

If you’re in need of assistance to establish or clean up your email reputation, my consulting firm does email deliverability consulting for many clients. Our services include:

  • Email list cleansing to ensure known bounces and disposable email addresses are removed from your system.
  • Migration to a new email service provider (ESP) with IP Warm campaigns that ensure you ramp up with a solid reputation.
  • Inbox placement testing to monitor and track your inbox vs. junk folder placement.
  • Reputation repair to assist good email senders to build back up a solid email reputation for higher inbox placement.
  • Responsive email template design, implementation, and testing for any email service provider.

If you are sending at least 5,000 emails to any single mailbox provider, we can even audit your program to provide you with feedback on the health of your overall email marketing program.

DK New Media Email Consultants

The Origin of the Word SPAM

Oh, and in the event, you didn’t know where the word SPAM came from… it’s from a Monty Python sketch regarding the popular canned meat product.

Douglas Karr

Douglas Karr is CMO of OpenINSIGHTS and the founder of the Martech Zone. Douglas has helped dozens of successful MarTech startups, has assisted in the due diligence of over $5 bil in Martech acquisitions and investments, and continues to assist companies in implementing and automating their sales and marketing strategies. Douglas is an internationally recognized digital transformation and MarTech expert and speaker. Douglas is also a published author of a Dummie's guide and a business leadership book.

Related Articles

Back to top button