One of mankind’s most innate attributes, curiosity is as natural to us as breathing. It’s this emotion that has driven every little discovery and every advancement in science, technology, language, industry, and human development.

Indeed, as Oscar Wilde aptly put it, “the public have an insatiable curiosity to know everything.” As an email marketer, what if you could appeal to this innate desire in people to boost your email open rates?

Here’s where curiosity email subject lines come in. This comprehensive guide will help you understand what they are and why they work. You’ll also learn how to create subject lines that spark the recipient’s curiosity to boost open rates and conversions.

Let’s get started.

Why are subject lines so important?

In a world where 319.6 billion emails are exchanged every day, email overload is very much real. When you have a ton of emails sitting in your inbox vying for your time and attention, you need an easy hack to weed out the unimportant ones.

For most people, this involves a quick evaluation of the email subject line.

An email subject line is one of the first things a recipient will scan through (besides the sender’s name) to decide whether to open an email or not. It’s an important consideration because it starts off the experience they’ll have with your campaign.

If you don’t take the time to make your subject lines captivating enough, your emails can quickly end up in the trash. Worse, your readers may even unsubscribe from your mailing list — even though the content of your emails may be useful and relevant to them.

That’s why email subject lines are so important — they may well be your first and final shot at connecting with your audience.

How to craft effective email subject lines

Did you know that email newsletters are the third most popular content type used by B2B marketers? They’re also the most effective at nurturing leads.

As an email marketer, you need to craft irresistible subject lines that catch your reader’s attention and make them want to read further. By following a few general best practices, you can greatly improve the performance of your email campaigns.

1. Understand your audience

If there’s one thing that’s non-negotiable when it comes to running an email campaign, it’s to make sure that your content is relevant to your audience. People may have different reasons for subscribing to your mailing list — it’s your job to figure out their motivation.

What does your audience care about? What are their needs, frustrations, fears, and inspirations? Use this information to segment your audience and create subject lines and content that resonate with them. Besides their names, you can also use their location or interests to personalize your subject lines.

2. Keep it concise

According to one analysis by AWeber, 82% of email marketing experts use email subject lines of 60 characters or less. This isn’t surprising since most desktop email clients truncate email subject lines at around 60 characters. Mobile email clients, in fact, truncate them at around 30 characters.

Hence it is ideal to choose short and crisp email subject lines. Be specific and avoid being wordy. You could also use powerful, high-impact keywords to encourage readers to open your emails and take the action you want them to.

3. Avoid spam words

Did you know that spam messages still account for 45% of all email traffic in 2021? As an email marketer, you need to ensure that your emails don’t trigger your recipients’ spam filter and land up in their spam folder.

One of the ways that spam filters work is to scan incoming messages for certain “buzzwords” typically used by scammers. Subject lines with words like “100% free,” “amazing stuff,” “extra income,” and even “free gift” or “free trial” have a high chance of being flagged by spam filters. As such, it’s best to stay away from the following list of spam trigger words.

Image source

What are curiosity subject lines and why do they work?

Now that we’ve covered the basics, let’s dig deeper and find out how to craft compelling email subject lines by appealing to the reader’s curiosity.

Curiosity email subject lines leave out just enough information to create a sense of intrigue and pique people’s curiosity. They play with our innate desire for knowledge and evoke a feeling of deprivation that makes readers want to open your email to learn more.

For example:

  • Can’t decide what to eat? This can help
  • 5 ways to make your “summer” diet stick this time (Do #2 right now!)
  • A little something for when keeping calm is difficult

Essential attributes of curiosity subject lines

As you can see in each of the above examples, these subject lines spark curiosity in the reader’s mind and provoke them to find out more. However, you must know the difference between curiosity and clickbait.

To that end, you need to know the essential attributes of curiosity email subject lines, so you don’t lose the trust of your audience and hurt your reputation.

1. The information gap

Professor of psychology, George Loewenstein, says that curiosity builds when the focus is on what’s missing rather than on what’s present.

As such, every curiosity subject line must present an information gap (or a curiosity gap). It’s the gap between what’s present (the information we know) and what’s missing (the information we don’t know). Here’s a great example from CoSchedule:

“Life gets crazy. So I saved this for you” is effective as a curiosity subject line because it makes the reader wonder — “What have you saved for me?” It creates an information gap that focuses on what they don’t know and urges them to seek the missing information in the email.

The body of the email talks about extending an exciting “half-off” offer on the Headline Studio Pro for one more day. As you can see, the subject line draws readers in using the information gap while the body satiates their curiosity.

2. The closure

Presenting an information gap in your subject lines is a good strategy to make your readers want to open your emails. Yet, it can backfire if the content inside doesn’t deliver on that promise.

An essential attribute of curiosity email subject lines is that the email body must bridge the information gap. In other words, it must provide closure.

Clickbaity emails that trick or mislead readers into opening them are sure to land up in the spam or get blacklisted. If you don’t follow through with the information you hinted at (in your subject), it can cost you your reputation.

When it comes to email marketing, Swiggy stands tall with its skillfully crafted emails. As you can see in the example below, the body of the mail does justice to the subject line.

It bridges the information gap by letting you know that the best thing to do on a family night is to order the favorite foods of your loved ones. It’s effective because it doesn’t meander and comes straight to the point.

3. Curiosity power words

Words can persuade. Power words trigger emotions (such as fear, excitement, astonishment, trust, vanity, etc.) and compel people to take an action.

Curiosity power words toy with our innate sense of intrigue to evoke our inner thirst for knowledge. Words like “elusive,” “hush-hush,” “privy,” “top secret,” and “little-known” can load your subject lines with curiosity and compel readers to find out what’s inside your email.

This email from Bath & Body Works is impactful because of its subject line — “Black Friday Secrets revealed!” The word “secrets” is a high-impact curiosity power word that hooks the reader and compels them to open the mail.

4. The intrigue

An effective curiosity subject line needs to create just enough intrigue that teases readers — but doesn’t give everything away. Giving away the best part won’t make your readers want to open your email, and that would be counter-intuitive.

Instead, they should raise questions in people’s minds and make them wonder what’s going on. Here’s a great example from Gong.

The curiosity subject line “Don’t Ask Me” instantly makes the reader wonder — “What?” Of course, there’s only one way to know the answer. Open the mail.

As you can see, the body includes a testimonial from Colleen — a happy customer who leveled up their sales team by following some great advice that was shared at one of Gong’s webinars. It ends with a call-to-action that invites the reader to sign up for these webinars so they can level up their sales team as well. Just like Colleen.

The subject line does a great job at intriguing the reader, getting their attention, and pushing them to take action — but it doesn’t give anything away. That’s why it’s so effective.

5. Open-ended questions

Questions in email subject lines can be great at piquing the readers’ curiosity. However, you must remember to ask open-ended questions only. Close-ended questions that have a yes/no answer are unlikely to generate enough interest or compel the reader to open your email and learn more.

This email from bigbasket uses an open-ended question in its subject line to generate interest and spark curiosity in the reader’s mind. It encourages them to open the mail and learn the history behind celebrating Labor Day.

The email delivers on its promise by sharing the story and ends with a beautiful message to thank every laborer who makes our lives easy. A heartwarming call-to-action at the end that encourages the reader to thank the bigbasket workforce makes this email even more effective.

Wrapping up

Curiosity subject lines can help you cut through the noise and grab the attention of your email subscribers. However, you need to craft them carefully following the guidelines mentioned above.

Make sure that your subject line presents an information gap and your email body bridges it. Use curiosity power words and open-ended questions to spark intrigue, but don’t give everything away. Captivating email subject lines can go a long way in boosting your open rates and making your campaigns immensely successful.

Read more: