6 Ways that Subject Line Writing Has Changed

August 20, 2019 | 9 minute read
Chad S. White
Head of Research, Oracle Digital Experience Agency
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Have your subject line writing strategies and tactics kept up with the times to get more returns on your email marketing? Hear what the experts at Oracle Markeitng Consulting have to say.

Check and see if you’re accounting for these six changes in subject line writing, going from the oldest to the newest trend:

1. Subject Lines Need to Work with Preview Text

Everyone knows that subject lines are super important. That’s why they’re the most tested email element. However, preview text is also really important, since it’s the third piece of envelope content, along with the sender name and subject line. But it gets far less attention and is less than half as likely as subject lines to be regularly A/B tested.

“Your preview text is your second chance to catch a reader’s attention,” says Lizette Resendez, Associate Creative Director and Copy Director for Creative Services at Oracle Marketing Cloud Consulting (OMCC). “If emails are the feature film, think of the subject line as the trailer and the preview text as that opening scene. You need a great opening scene to really reel the viewer in from the get-go.”

To do that, brands must first control what text appears in the preview underneath or to the right of the subject line in the various inboxes. You can do that by using either visible or hidden preheader text, which is the text positioned at the very top of the body of your emails. The good news is that nearly every major brand is actively controlling their preview text. Today, the opportunity is largely around fully optimizing that preview text so it’s working its hardest. 

“Your preheader is a great place to mention an extra perk, add supporting details, or throw in a clear call-to-action that entices customers to open the email and take action,” says Kelly Moran, Associate Copywriter in Creative Services at OMCC. “The biggest preview text mistake that I see pretty often is brands wasting the space by repeating information already included in the subject line. That’s valuable real estate! Give subscribers new information.”

Here are seven approaches to using preview text to support your subject lines, some of which you can see in action in envelope content of the emails below. Moreover, in the Home Depot example below, you can see the use of a preview text hack that allows marketers to create white space that pushes out any unwanted preview text. 

“That hack can give your message clean white space that other brands don’t have, making your message stand out even more in the inbox,” says Resendez.

Also, see how to get started doing more insightful A/B testing to deliver more impactful marketing with Oracle Maxymiser Testing and Optimization using our help center.


2. Subject Lines Can Include Many More Visual Elements

For a long time, subject line writers had to be content with periods, dashes, slashes, and the other standard symbols on keyboards. Then in 2012, inbox providers started supporting the use of special characters like stars, and their use became somewhat common. But when inbox providers added subject line support for emojis in 2014, that’s when the visual palette of the subject line exploded. That’s both a good thing and a bad thing.

“Emojis are friendly and enticing,” says Monica McClure, Senior Copywriter on OMCC’s Creative Services team. “When used effectively, they can make your subject line stand out. When used badly, they can make your email look like spam.”

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The first challenge with emojis is determining if using them at all is appropriate for your brand, considering that in general they come across as casual and cutesie. 

The second challenge is that they’re not supported on older desktop operating systems. For the vast majority of B2C brands, which are likely to have lots of mobile email readers, emoji support is largely a non-issue. But, if you’re a B2B brand operating in an industry that tends to have long tech replacement cycles like healthcare, then subject line emoji support may be quite poor.

And the third challenge is that even when they are supported, they are not rendered consistently—which is to say that the same emoji will look different in Gmail, the native iPhone email app, and desktop Outlook, for example. You can check out the variations on any emoji listing on Emojipedia. Generally speaking, if you stick with the more commonly used emojis, you will avoid the more jarring differences in renderings.

If you’re not ruling them out completely, then we recommend establishing some rules of engagement.

“Come up with a kind of style guide for emojis, just as you would for copy and design,” says McClure. “Emojis should form an iconography that aligns with the brand, and they shouldn’t stray too far from that even if it may seem appropriate to the particular content of an email. Ask how the emojis you’re using connect to your brand.”

For example, with Oracle Marketing Cloud Consulting client Hawaiian Airlines, we try to include emojis that reflect their unique position as Hawaii's hometown airlines. In one email, we used the subject line “? Hawaii flights start at $398 RT | Explore the Rainbow State.” We then carried that into the email, which featured a rainbow scene.


In addition to ensuring brand alignment with your emoji choices, we also recommend that you not replace words with emojis. Instead, use emojis as intensifiers to stress certain words, and as a divider to separate ideas or items in a subject line.

3. Subject Lines Need to Demonstrate Contextuality, When It Exists

Automated emails are increasingly common, with a growing percentage of brands generating the majority of their email marketing revenue from these high-ROI messages. Because these emails are sent in response to a subscriber doing something, a subscriber not doing something, an event occurring, or an internet-connected device being triggered, it’s important to communicate this context to subscribers. 

Answer the question: Why is the subscriber receiving this particular email?

“Here’s your chance to truly speak one on one with your customer, speaking about things that they actually care about—like that handbag they put in their cart or the wool blanket they were browsing as a potential seventh wedding anniversary present,” says Resendez. “This is as close as you can get to actually having a conversation with your customer via email. Make sure the subject line is direct and written just for that customer. Make it personal.” 

Moran also stresses the one-to-one nature of automated emails and how personalization amplifies the impact of these emails. “Triggered messages often outperform other emails for a few reasons, and the opportunity for personalization is one of the key ones,” she says. “Adding a personal touch to the subject line—such as “RSVP successful: See you in Tampa, Susan”— helps it stand out from unprompted, non-triggered emails in their inbox.”

Moran points out that preview text is also an important part of communicating the contextuality of an email, and that personalization can be placed there instead of in the subject line. For example, Urban Outfitters’ cart abandonment emails use the subject line “Hey…you left something at our place…” and then the preview text is the name of the item in their cart along with the item’s price.

While sending an automated email immediately after its trigger condition isn’t optimal or appropriate in every case, it often is for an action-triggered email like a welcome email. That immediacy helps the subscriber connect their actions to why they’re receiving the email.

4. Machine Learning Can Help Write Subject Lines

A number of AI-powered tools now exist to help marketers write more effective subject lines, including Persado, Phrasee, and Touchstone. While these tools can be powerful, suggesting words and phrases you would have never thought of, we’re in the early days of AI-powered copywriting. That means that marketers don’t always set the right goals for the AIs and that the AIs can produce subject lines that don’t sound natural and can get very off brand.

Check out this full exploration of how to use AI subject line and copywriting tools successfully.

5. Voice-Assistants Are Now Reading Our Subject Lines

After becoming much more visual over the past five years, subject lines are suddenly becoming auditory, thanks to the explosive adoption of voice-assistants like Siri and Alexa and their ability to now read a user’s emails to them. While the adoption of this behavior is low, the experience of reading a promotional email’s subject line can be uneven and, in some cases, almost nonsensical. That’s because voice-assistants read out the names of emojis, letters that have a space on either side, and some punctuation marks.

For example, as we pointed out in this deep dive into how marketers can adapt to voice-assistants reading emails, Siri reads the subject line below as “Sparkle sea ell ee ay en eye en gee sparkle ess ay ell ee sparkle.”



If using voice-assistants to read emails becomes a more common behavior, brands will likely have to be much more careful and deliberate in their use of emojis and may have to completely abandon certain visual elements and styles, such as placing spaces between letters of a word.

6. Brands May Need to Write Alternative Subject Lines, if They’re Using Email Annotations

Powered by a mix of microdata and JSON code, Email Annotations allow for the potential for an email’s preview text to be replaced by enriched previews when viewed in Gmail’s Promotions Tab. Those rich previews in the inbox can include an offer, discount code, expiration date, and featured image. Because those additional elements have the potential to be redundant with the content of the subject line, Email Annotations also allow for the creation of an alternative subject line that only appears when a rich preview is displayed.

For instance, if an email’s subject line is “Save 30% off all purchases | Ends Wednesday!” then both the discount amount and the expiration date would become redundant when a rich preview with that information is displayed. In that circumstance, brands would be able to have an alternative subject line appear that would highlight other messaging instead.

Want to know if Email Annotations are worth using? We have a full discussion of the opportunities and concerns around Email Annotations in the Gmail Promotions Tab

Despite all of these changes to subject line writing, the goal of a subject line remains the same: to get those subscribers who are most likely to convert to open and engage with the email—and, to a lesser extent, dissuade those who are the least likely to convert from opening the email and becoming frustrated or disappointed to the point that they unsubscribe.

“Generally, subject lines should be clear, short, and on-brand,” says McClure. “They shouldn’t sound click-baity or sales-y. They should lead with the most relevant information, according to the primary goal of the email.”

Keep these foundational tenets of subject line writing in mind as you think about how you adapt to these six subject line writing trends.


Need help with your email subject lines? Oracle Marketing Cloud Consulting has more than 500 of the leading marketing minds ready to help you to achieve more with the leading marketing cloud, including expert copywriters on our Creative Services team.

See how the experts at Oracle Marketing Consulting can help:



Chad S. White

Head of Research, Oracle Digital Experience Agency

Chad S. White is the Head of Research at Oracle Digital Experience Agency and the author of four editions of Email Marketing Rules and nearly 4,000 posts about digital and email marketing. A former journalist, he’s been featured in more than 100 publications, including The New York Times, The Wall Street Journal, and Advertising Age. Chad was named the ANA's 2018 Email Marketer Thought Leader of the Year. Follow him on LinkedIn, Twitter, and Mastodon.

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