Rover’s Subject Line and the Curiosity Gap

In this issue you’ll see:

• How Rover’s subject line hooked me with one simple, 4-word question

• What the curiosity gap is and why it’s critically important to your subject lines’ performance

• How you can use curiosity gaps in your subject lines, headlines and crossheads

Let’s dig in.

THE BREAKDOWN

Rover’s seemingly simple question

Writing a subject line is easy.

Writing a good subject line—one that actually gets the open—is hard.

Which is why I consider the promotions tab of my inbox one of the best swipe files ever.

(Yours probably is too.)

Look at the emails you opened.

Now look a little closer.

Take a second to think:

Why did you open that email?

This is one of my favorite questions to ask because the answer invariably provides a quick lesson in what motivates readers to take action.

Without further ado, here’s the open-worthy Rover subject line:

Before we continue, to clarify:

Beets is my cat. For any cat lovers in the room, like me, you may wonder many things about your cat, like:

• What causes your cat to partake in a round of zoomies?

• Is your cat mad when he scratches at the scratch post? (He seems mad…)

• And, yes, does your cat have feelings?

So, yeah, this subject line got the click. 😜

The subject line & preview

Subject line: Does Beets have feelings?

Preview: While cats do have feelings, they don’t experience them in quite the same way…

Here’s what works:

• Personalization: Using my cat's name in the subject line—pulled from my user profile—is a clever way to increase the email’s relevance (see more on the self-reference effect for why this really matters).

• Specificity: The preview indicates that the email is specifically about cats. This is important—pet owners know that cats and dogs are different, so this little detail increases the email’s perceived relevance.

• Curiosity: This is the biggie. Rover may have pulled this question from speaking with their customers. But, more likely, they conducted SEO research and reviewed page analytics to see which questions get a high volume of searches.

Typically, I’d caution against closed-ended questions for key messages like subject lines, headlines and crossheads. Here’s why:

Closed-ended questions elicit a yes / no response from the reader… and “no” is typically pretty terrible for conversions because it’s the point where your readers will disqualify themselves from your offer.

In this case, the closed-ended question works well because I don’t have a definitive answer to the question. There’s a big difference between a subject line like “Do you need help with your bookkeeping?” (this is an easy “no” or “yes” based on the reader’s circumstances) and “Does Beets have feelings?”

Here’s what I’d test:

Let’s look at the inbox preview for mobile and desktop. First, the mobile view:

Followed by desktop:

Notice anything?

My two cents: 

While it proves relevance by mentioning cats, the preview also answers the question the subject line is asking! I don’t need to open the email to see the answer.

In this case, I’d test a preview that builds on the open loop the subject line creates, rather than give away the answer. The trick is to ensure “cat” or “cats” still appears in the first ~30 characters so the specificity is preserved and visible in mobile view.

THE PSYCHOLOGY

The curious case of…

The curiosity gap is the space in our brain that separates what we currently know from what we want—or need to—know.

Curiosity gaps—sometimes called information gaps—have been widely studied over the last several decades. Researchers have studied how it can impact work engagement, motivate students to perform better in class and, yes, drive clicks.

By using a question that cat owners presumably wonder regularly, Rover taps into the curiosity gap big time.

THE ACTIONABLE TIP

Mind the (curiosity) gap.

Here’s the key strategy you can swipe for your subject lines and previews:

Use your subject lines and previews to open curiosity gaps that only opening your email can close.

Here are 3 simple ways to open curiosity gaps:

• Ask relevant provocative questions you know your audience is hungry to answer (like Rover did).

• Tease a desirable solution that you’ll reveal in your email. (Example: “See how 2 simple tweaks grew sales by 43%”)

• Intentionally use incomplete information by replacing proper nouns and/or common nouns with demonstratives or pronouns. (Example: “This might be sabotaging your sleep”)

Most importantly:

If you use the curiosity gap in your subject line, please, for the love of all that’s good, make sure your body copy actually closes the curiosity gap. 

Failing to close the gap typically annoys readers, which isn’t good for engagement, long-term list health or conversions.