The Best Subject Lines Have Curves - Revinate

The Best Subject Lines Have Curves

Jennifer Lopez has them. Kim Kardashian definitely has them. And every subject line should have them. I’m talking about curves: They’re the secret to the success of not just your favorite celebrities, but also the most effective subject lines.

You’re probably wondering how a subject line can have curves, right? The C.U.R.V.E. formula was created by Alex Williams, the Creative Director & Digital Strategy Director at Trendline Interactive, who spent years writing and testing email subject lines. It stands for Curiosity, Urgency, Relevancy, Value and Emotion.

According to Mr. Williams, a good subject line must have at least two of the five C.U.R.V.E. elements to succeed in achieving high open rates. I’ve broken it all down for you here:


Human beings are curious creatures by nature. When crafting a marketing email, you should use a subject line that signifies that there is something to be discovered.

Example: Here’s what happens when you vacation in Maui
Example: This is what luxury should feel like

But, exercise caution. Don’t promise something in the subject line that the email itself does not deliver. Misleading people into opening your emails will hurt your credibility and they probably won’t open your next email.


When people feel a sense of urgency, they’re more likely to make decisions quickly. Nobody wants to feel like they’ve missed out on a great opportunity or offer.

Example: Now’s your chance! Sale ends tomorrow.

Keep in mind that urgency is only effective when it’s associated with relevancy and/or value. If you’re going to offer a sale, make sure to offer more available dates than black-out dates. Otherwise, you may also damage your credibility.


It’s easier said than done, but the content you send out to your subscribers should be as relevant to them as possible. For example, sending a campaign with the subject line “The perfect summer family getaway awaits” to a subscriber with no children is a surefire way to get them to unsubscribe.

Instead, you want to segment your subscribers into groups based on their preferences and needs. You have endless amounts of data on your past guests stored in your PMS. Use it to your advantage. Customers at Revinate have found loads of success when segmenting their database by geography, past stay dates, and rate codes, just to name a few.


The most important question you can ask yourself when crafting a subject line is, “If I were the recipient, would this be of value to me?”

If you want to build great relationships with the guests in your email database, you must always provide value and ask for very little in return.


It’s no secret that humans make decisions based more on emotion than logic. That’s why it’s so important to trigger the right emotions in people, thus driving them to take action and open your e-mail.

One of the best ways to do that is to appeal to their senses by using words that convey sight, sound, touch, taste, and smell.

Here are some examples:

Sight – Water so blue, you have to see it with your own eyes
Sound – Fall asleep to the sounds of waves crashing. Upgrade to an ocean view.
Touch – Feel the warm sand between your toes this winter
Taste – Everything tastes better in paradise
Smell – Wake up and smell the pineapple

Keep these tips in mind the next time you write a subject line, and you’ll stay ahead of the curve!