The Best Email Subject Lines of 2021

The best email subject lines of 2021

It’s that time of year again!

Last year I shared my favorite email subject lines of 2020 and this year I’m back with the best of 2021.

As I mentioned in last year’s article, this list is somewhat subjective (as what may grab my attention may not interest someone else), but what is NOT subjective are the persuasion techniques being used in each subject line.

To help you understand each strategy (and how you may use it for your own business), I’ve grouped the subject lines into 4 categories:

  • Personalized & relevant
  • Piquing curiosity / offering new information
  • Attention-grabbing
  • Humorous

While there are many more persuasion techniques outside of the list above, the examples below may give you some ideas that you can use for your own email marketing in 2022 and beyond.

Let’s see which email subject lines from 2021 made the list!

Category 1: Personalized & relevant

The #1 way to engage your subscribers is with personalized content that’s relevant to them.

Personalization and relevance occur when you combine customer information (like demographics, purchasing behavior, their goals, interests, challenges, pain points, etc) with segmentation.

Capturing customer information can be done at any point throughout the customer journey (i.e. – before or after purchase, during onboarding, when cancelling, etc) and can be used to help you segment your lists and create content that will be most relevant for each audience type.

Here are a few examples of how my information was used to create more relevant content.

Personalizing by name

When I first signed up for Chewy, they asked for my dog’s name, birthdate, breed, and other information that would allow them to target me more specifically.

In the example below, Chewy grabbed by attention by using my dog’s name (Scully) in the subject line and using language that would appeal to any dedicated pet owner (spoiling your dog).

Personalizing by location

In the example below, Caviar combined multiple tactics to get my attention: my past order history, my location, and a limited-time offer to create a sense of excitement and urgency.

Petco did something similar when I updated my shipping address; we moved locations and then suddenly I got an email speaking directly to the pain point I was experiencing in that moment.

Personalizing by birthdate

By asking for my birthday upon sign up, The Sill is able to send me personalized content like the example below which highlights my horoscope sign.

Email subject line Example 2 using personalization and relevance 2021

Personalizing by action

By opting in to AmazonSmile, Amazon can send me updates about the charities that are important to me, making me feel as if I’m personally making an impact.

Email subject line Example 3 using personalization and relevance 2021

For your own business, think about the information you already have about your customers (i.e. – name, birthday, location, purchase history, behavioral data, email opens/clicks, etc) and how you can use that to create more personalized and/or relevant content.

If you don’t have any customer information yet, start collecting it at various stages of customer journey so you can begin leveraging it in the future (or you can collect it the old fashioned way through surveys, interviews, etc which you can learn through my customer research course).

Category 2: Piquing curiosity / Offering new information

In Eugene Schwart’z book, Breakthrough Advertising, he advocates using “mass desire” (universal wants/needs all humans crave) to create more persuasive marketing — and at the top of that list is “curiosity” (or “the desire to learn and gain knowledge”).

While the emails below may not always be a “hard sell,” they’re using the power of curiosity and desire for knowledge to build trust with subscribers while also softly promoting their products.

Here’s a few examples from 2021:

Information about a specific pain point

When you have an elusive, difficult-to-solve problem (like acne), the idea of learning new information that may help you finally crack the code is irresistible.

In the example below, ZitSticka combines the promise of new information with authority (“The Science”) and the Open Loop technique (“Want to see what’s inside?”) to pique curiosity and drive engagement.

Example subject line using curiosity and education, example 1

Example subject line using curiosity and education, example 2

Knowledge that fulfills multiple needs

Combining multiple desires or needs into a single subject line is a surefire way to engage your subscribers.

In the example below, Kat Maconie is providing me with information that not only piqued my curiosity (learning about new fashion trends), but it also helped me fulfill another “mass desire” of mine (wanting to achieve social status/significance through my attire).

Example subject line using curiosity and education, example 3

Tapping into fear & anxiety

Like mass desire, combining new information with negative emotions like fear, anxiety, anger, or embarrassment can be incredibly motivating.

In the example below, the dermatologist (who is a trusted authority figure) combined a common, but specific fear (skin cancer) with new information that could potentially save your life.

Example subject line using curiosity and education, example 4

Here’s a quick exercise you can try for your own business: make a list of your customers’ goals and pain points. Is there anything on that list that could be made into some kind of educational content?

For example, let’s say you’re a shoe brand and your customers’ pain points include things like foot pain and durability of the shoes themselves. You could partner with a doctor and create a guide around how to minimize foot pain while wearing fashionable shoes or create a blog post with tips and tools for how to make your shoes last.

While you may not always be pushing your product front-and-center with this type of content, you’re still providing value and building trust with your audience (plus, you can always do the soft sell using this approach).

Category 3: Attention-grabbing

According to this article from Tech Jury, the average office worker receives 120 emails per day, which means your emails need to stand out now more than ever.

One of the best ways to do that is with subject lines that jolt the reader out of their routines so they stop deleting and start reading.

Here’s how you can do it:

Surprise them with something unexpected

According to this 2021 article from Inc, the #1 way to grab attention during a speech is to “start with the unexpected” and the same rule can be applied to your email subject lines.

In the example below, Drizly combined something totally unexpected (“our psychic dog”) with something personalized (“picked you some drinks”) to grab my attention.

Example of an email subject line using unexpected content and language

Even though it’s kind of silly, it was still surprising and different enough that I paused, opened, and perused the email (I mean, I just had to know: did the dog know something I didn’t?!).

The two examples below also use the element of surprise as a way to grab attention. 

The first works because they not only used my name in the subject line, they also made it seem as if the email was actually from me which was both surprising and somewhat alarming.

Of course, once I read the pre-text, I knew it was a marketing message, but the use of my first name in two places (and using the word “personal”) was too powerful to ignore.

It’s worth noting that this approach could get you marked as SPAM, so I recommend treading lightly (i.e. – only using the first name in the subject line vs in the sender line, as well).

Example of an email subject line using unexpected content and language

In the example below, the sender grabbed my attention for a few reasons: first, he used language that felt very personal, like something my husband or friend would send.

He also asked me to call him, which is the exact opposite of how I would normally respond to an email. Finally, he used the pre-text “it’s kinda urgent” to create — you guessed it — a sense of urgency.

While I didn’t end up making the call, I did feel like this was a great example of combining familiar language with an unexpected request, which is something any business can do.

Example of an email subject line using unexpected content and language

Here’s another example: Kevin Smith was able to grab my attention by using language I don’t normally see in my inbox (“what went wrong?”).

Example of an email subject line using unexpected content and language

For your own audience, think about the words/phrases that may be recurring in their inboxes and see if there is an opportunity to incorporate language they may be different, unique, or even shocking.

For example, instead of the best subject lines of 2021, I could try “the worst subject lines of 2021” which would be more unexpected (and perhaps more attention grabbing).

The example below from Reformation is actually a great example of this very concept; they combined multiple strategies to create a very effective subject line.

Email subject line example using unexpected language as a means of persuasion

While Reformation is known for pithy, one-liner-style subject lines, there is a method to their madness. Below is a breakdown of the four strategies they’re using in this single subject line:

  • Unexpected language (“don’t open this”)
  • Punctuation (using all caps to stand out)
  • Humor (“unless you like blue”)
  • Reverse psychology (saying “don’t open this” makes you want to open it)

Get emotional

Going back to that Inc article I mentioned above, #6 on the list is to “arouse emotion” which is yet another technique that translates beautifully from speeches to subject lines.

In the example below, Annie Grossman takes a highly charged topic (gun control) and combines it with something unexpected (a dog trainer’s take on it) to create a subject line that arouses an emotional response.

Example of an email subject line using emotion and unexpected language

A similar technique was used by this non-profit organization to arouse feelings of anger and sympathy for a teacher who was fired for teaching a “controversial” topic.

This subject line not only plays into our emotions, it also uses the Open Loop technique by only giving us a small, tantalizing taste of a much bigger story.

Email subject line example using open loop and emotion to drive engagement

Delight them with something exciting

Even if what you have to offer isn’t all that exciting, there are ways you can make it seem more exciting like how Food & Wine does in the example below.

Example of an email subject line using excitement, surprise and delight

This approach not only uses the Open Loop technique (you have to open the email to see what you’re getting), but they also lead with an emoji and use punctuation (parenthesis) to stand out aesthetically, which is important in a crowded inbox.

Similarly, The Arrivals sent the email below just after the initial rush of Black Friday, giving you the impression that even better deals were still waiting to be discovered (and using all caps to grab attention).

Example of an email subject line using emotion and unexpected language

Here’s an exercise you can use to weave more “unexpected” content into your email subject lines — take your marketing calendar (or whatever ideas you have for the year) and consider the opposite of everything you have on that list.

For example, instead of a blog post about achieving your goals, create a blog post about a time that you set a goal and failed (and what you learned as a result).

Category 4: Humorous 

While the jury is still out on whether or not humor can increase persuasiveness, some research shows that humor can help you form social bonds with others.

According to this article from Berkley University, “shared laughter may communicate to others that we have a similar worldview, which strengthens our relationships,” which means using humor in your email subject lines may help you build connections with your audience.

While not everyone will find these examples funny (humor, after all, is incredibly subjective), I personally found them to be charming, which in turn, made me like the brands even more:

Examples of email subject lines using humor as a means of persuasion

Examples of email subject lines using humor as a means of persuasion

Examples of email subject lines using humor as a means of persuasion

Examples of email subject lines using humor as a means of persuasion

Examples of email subject lines using humor as a means of persuasion

For your own business, consider testing some humor-driven subject lines to see how they pan out; try puns, a play on words, a witty turn of phrase, a nod to pop culture, or something that’s currently trending in our world to see what works for your audience.

What are your favorite subject lines of 2021?

Are there any that I missed? Are there any email lists I should join? Are there any techniques you find most or least effective?

Tell me all about it below or by sending me an email directly:

As always, I truly appreciate you reading and hope you found this helpful. Cheers to a happy, healthy holiday and a wonderful New Year!

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