5 Best Email Subject Line Strategies to Boost Customer Responses

5 Best Email Subject Line Strategies to Boost Customer Responses

Do your newsletter subscribers or potential customers ignore your attempts to contact them? Check out our five subject line strategies to make customers react to your email.

Poor email response rate is a common issue for many companies interested in this type of email marketing.

According to eMarketer, only 30% of email list subscribers decide to buy a product offered to them in an email. And this is not surprising. In the era of the highly competitive market and promotions that pop out everywhere, people don’t spend much time reading through promotional emails unless they are instantly attracted to them.

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Naturally, your email subject line is primarily responsible for creating this instant attraction. The choice of the leading sentence can dramatically impact your email marketing destiny.

Accordingly, these words have become a popular research field for copywriters and email communication enthusiasts. And that's why we've researched and picked the strategies that have shown great results in boosting customer responses.

1. Spice it up with Emojis

To make them want to react to your email, first, you have to make them want to read it. And we're starting this guide right there.

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According to Mobile Marketer, the well-used emojis in subject lines give you a higher read rate than text-only subjects. More precisely, the emoji-enriched subject lines had 3.29% higher unique open, 6.28% higher unique clicks, and 18.93% higher click-through rates.

However, it's important to realize that not all emojis on all occasions have the same chances of boosting customers' engagement. So, double-check if the chosen emojis fit your brand identity and the occasion they use.

Let's check some useful tips that you should stick to when choosing the ideal emoji for your subject line:

  • Choose the emojis to express an idea instead of just adding them to a sentence
  • Be careful not to use too many emojis since it may cause an overwhelming or spam effect
  • Check if the chosen emoji appears similarly on different browsers and apps to avoid misunderstandings

Good examples of this practice come from Alto:

practice come from Alto

And a cookie company based in San Francisco:

cookie based company

2. Make Them Curious

No matter how great the content of your email is, if its subject line doesn't stand out, you probably won't even make your customers read it – not to mention react to it. Accordingly, you have to think about your readers if you want to receive positive feedback.

For starters, if you had to pick the most attractive lines from those listed below, which ones you choose?

Group #1:

  • Daily Review
  • The Latest Newsletter
  • Monthly Catalogue Is Now Available

Group #2:

  • Is Your Price, Right? [Namecheap]
  • On the hunt for the perfect item? The search ends here. [AliExpress]
  • Relationship problems? This is magic. [Marie Forleo]

Chances are we all agree that the subject lines from the second group sound more appealing. But what makes the second approach more likely to provoke a response?

We're asking a question and doing it intriguingly, which commonly makes customers think about the content and react to it. So, instead of just trying to communicate your brand message by writing the subject line like you don't care, try to make your lead message more captivating and unique.

3. Make it useful

Did you know that, in practice, 69% of people who receive an email report it as spam based on the subject line only? And one of the common reasons for this behavior is that they don’t see any value in your subject line.

spam based on the subject line

In accordance, if you want your email readers and (potential) customers to increase your business value, then you should not only invest in improving the value you offer to them.

You should also show that you’re doing so from the start of your interaction - in the subject line itself. Otherwise, they may not even get a chance to see you’re offering something useful in your email.

Accordingly, your subject line should show that you’re willing to share your knowledge, which may look like some of these great real business examples:

  • How to Survive Your Next Overnight Flight [Thrillist]
  • Learn a Language with Only 5 Minutes a day [Duolingo]
  • How to Run an Instagram Campaign from Start to Finish [Later]

Besides, implementing this strategy can make it even more effective by enriching it using a free online quiz maker for your business.

This way, you create an excellent opportunity for the email readers to learn and react to your message. But don't forget to catch their attention by using the subject line to emphasize there's a quiz in the email, which may look like these examples:

  • Find Out What’s Unique About You (Online Quiz Inside) [Michael Hyatt]
  • Take Our 1-Minute Online Quiz to See How to Get Better Results from your Facebook Ads [Facebook]

4. Make It Engaging and Challenging

If you see a button saying "don't press," will you at least think about doing it?

Well, the same goes for your readers.

If you make them think about your subject line, they will be more interested in opening the email and reacting to the content. It's in people's nature to react to dares, and your subject line can be a real daring masterpiece if you're creative enough. So, let's see how some major brands do this:

  • Don’t Open This Email* [Manicube]
  • ? a surprise gift for you! {unwrap} [Mary Fernandez]
  • Licking your phone never tasted so good [OpenTable]

Practically, as long as you avoid generic and boring lines that don’t seem to wrap up great content (whether it’s a just-for-fun, educational or promotional material), you are probably on the right path to increasing the readers’ engagement level.

In other words, don’t hesitate to be informal, funny, and bold since these mechanisms are most likely to trigger responses.

5. Offer Something Special

Last but not least, the limited-offer strategy makes readers react to your email. According to Invespcro.com, emails whose subject lines provoke a sense of urgency or exclusivity give up to a 22% higher email open rate.

So, what does this strategy look like in practice? Check it out:

  • Tonight only: A denim lover’s dream [Guess]
  • Complimentary gift wrap on all purchases [Rapha]
  • Good News: Your Pin’s price dropped! [Pinterest]

As you probably realize, based on your reaction to these subject lines, scarcity usually makes customers think more intensively about your offer. As you can see in the examples above, you can achieve this effect by:

  • Offering products or services in a limited time;
  • Offering a limited amount of exclusive products or services to subscribers;
  • Providing limited products or services under special conditions such as discounts, personalization, bonus gifts, etc.


As you can see, there are several pretty effective yet simple ways to create an impactful and engaging subject line that will make your customers react. Also, don’t forget to take your time to analyze which of the listed strategies is the most appropriate for your business before implementing one of them.

To create a perfect subject line, you should be unique and innovative and think about your brand and business values, as well as customers' profiles, needs, and preferences.

Finally, if you don't know where to start, remember that personalization is usually a significant first step toward success.

Angela White is an ed-tech enthusiast with a passion for writing for the consumer market in the areas of product research and marketing using quizzes and surveys. Having a knack for writing and an editorial mindset, she is an expert researcher at a brand that’s known for creating delightfully smart tools such as ProProfs Quiz Maker.

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