What is an Email Subject Line?

What is an email subject line to you? If people click to open your emails, then you’ve already written at least one.

Put simply, an email subject line is the 50ish character sentence you write that causes people to open your email (or not open). Publishers don’t often ask the question of what an email subject line is, because they open and answer emails every day. Every time you get an email, it comes with a subject line. If it’s well-written and clever, it will cause you to open. If it’s descriptive and urgent, it might even cause you to click a link once you’ve opened the email. But for the sake of broadening our glossary of publishing definitions, let’s take this email subject line definition even further.

In the past we’ve offered up what we feel are the most effective email subject lines for increasing open rates.

For example, if you use the words “reason why” in a headline, you may have dramatically higher open rates. An example might be “10 Reasons Why You Got Laid Off and they Didn’t” or “One Good Reason Why You Should Microwave Your Kitchen Sponge.” The Reason Why email subject line convinces the user “why” they should do something based on a number of “reasons.” People respond well to lists, and according to our testing, they respond well to reason too.

Another healthy email subject line formula uses the words “how to.” Specifically, we’ve found that “how to make” is the most popular version of this subject line. For example “How to Make a Cake in 30 Minutes or Less” or “How to Make $1,000 in 24 Hours.” The how-to subject line promises to reveal “how-to” achieve the benefit. It’d hard to write a bad how-to email subject line. Simply join a mouthwatering benefit to the words “how to.”

Download a FREE copy of Best Email Subject Lines for Selling Premium Subscriptions and Memberships and discover an extensive list of email subject line frameworks that are consistently proven to sell and boost revenue for publishers.

We have also talked a lot about professional email subject lines, using the same principles.

I once wrote “kickass” in a subject line for Mequoda and promptly got a few emails about it. A trickle of emails out of a few thousand isn’t the majority, but when people put “pen to paper,” you know there are more out there wanting to do the same. The email got a much higher open rate, but I hung my head, apologized, and updated the article, too.

If you’re a B2B publisher, you probably can’t say “kickass” and you can’t write subject lines about how to make a cake in any number of minutes or less, either. B2C email marketing is hard. B2B marketing in general is harder. But we do it anyway, even when Parenting magazines have five hundred likes on their Facebook posts and we have ten!

Because let’s be honest, B2C publishers tend to have larger email lists of consumers willing to spend $10 on a whim. B2B publishers have much smaller lists and are asking for their buyers to spend a hundred, or a thousand dollars. Maybe more. This is where writing professional subject lines make a difference.


We also think you should combine these formulas and make your email subject line work double duty.

Mix them up, man. Take this subject line and that subject line and tangle them up so they’re offering a reason why and a how to. Like, “How to Find Out the One Reason Why You’re Single” … or something.

List subject lines work well, and they work well consistently. But you can still improve upon a list subject line by adding a benefit headline to it. Instead of posting about 20 Country Slow Cooker Recipes (straight to the point) try a post about the Top 10 Lazy Skillet Meals.

How do your email subject lines perform? Let us know your most memorable, top performing subject lines in the comments!




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