Not only does spam email marketing betray the trust of customers, but it can also contain malware and viruses. Ultimately, you’ll want to avoid sending spam emails because your customers won’t read them.

Let’s look at what spam trigger words are, what gets emails sent to spam, and which spam words you should avoid when creating your email campaigns.

Trigger words are known to cause problems and increase the chances of your email getting caught in a spam trap. By avoiding these words in your email subject lines, you can dramatically increase your chances of getting beyond the filters.

Spam trigger words alone aren’t enough to send your email to spam. For instance, if you are offering a 3-for-1 discount sale, you can still advertise that in your emails and not get sent to spam. It’s important to understand all the factors that come into play when emails get identified as spam.

Your emails can get sent to spam if you:

Now that you know what not to do, let’s go over some best practices to ensure your emails steer clear of spam folders.

Email providers only want to deliver emails from high-reputation senders. To be a high-reputation sender, do the following:

If you meet these criteria, you can get away with using “classic” email spam words in your subject line and your email. The text surrounding the spam phrase also matters, as does your history as an email sender. If email providers don’t have a reason to mistrust you, they simply won’t.

When writing your email subject lines, you want to avoid:

Next time you sit down to write an email subject line, consult the exhaustive list below. In fact, you might want to bookmark this list so you can refer back to it every time you craft an email subject line.

So long as you use email marketing best practices and use spam trigger words within context, you can bypass spam filters. Spam filters have become much more sophisticated in recent years. Using one or two phrases won’t hurt you, but make sure to only email customers who want to hear from you and to always personalize your emails. Doing so will optimize the results of your campaign and keep you out of spam folders.

Editor’s note: This post was originally published in March 2013 and has been updated for comprehensiveness.