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Subject Line Optimization

It doesn’t matter how good the content is if nobody ever sees it!

While your customers and leads are consistently bombarded by email, the key to getting them to open, click and engage with your emails is to make it worth their while. Needless to explain why a high open rate leads to more engagement, it is also important that recipients willingly open their emails before taking other actions. And this is where subject lines and their optimization come into play.

A perfect subject line must convey your message without giving all the information away, but also convincing your recipients to spend time on your email and connect with your offering. Words are powerful enough to positively/negatively impact your score.

Since emails are delivered at scale, AI can help guide marketers for the most effective subject line copy specific to their customers. Zeta is here to provide insights on subject lines entered by you based on our learnings of previously resonated messages. ZMP also lets marketers view the most impacting words and tweak them in the subject line for better open rates. All in all, Zeta does the entire work for you! Let’s have a look at how:

1. From the menu on the left, select Campaigns > Broadcast. Click on New Campaign.

2. Name your campaign and click on Next.

3. Navigate to the Content & Audience tab and click on Zeta AI Insights on Subject Line under the Subject FIeld.

  • A panel for insights will appear displaying the best practices for you to draft your subject line.

4. Alternatively, you can add in your own subject line and let the platform score it based on its set best practices.

  • You can keep making changes to the subject line in order to score better.

  • You can also do an A/B Test to compare the results and choose better.

To learn more about this feature, watch this short demo.

Generating Subject Lines

ZMP has the ability to auto-generate subject lines for your marketing campaigns. Using cutting-edge technology from OpenAI (leveraging AI/ML), our tool takes into account your campaign history and tone selection, as well as our advanced subject line scoring model, to suggest subject lines that are sure to inspire you. And if you're in a hurry, you can even use our pre-made subject lines straight out of the box. Give it a try and see how easy it is to create engaging subject lines that will grab your customers' attention! 

1. As soon as you start typing the subject line, a Generate option will be enabled.

2. Click on Generate to display up to 3 new suggestions with the corresponding predictions on the scale of Poor, Fair, Good, and Excellent ratings.

3. Click on the next (>) arrow to see more suggestions. ZMP will display up to N (configurable) suggestions in a sorted order of predictions.

4. As and when you select one of the suggested subject lines, it gets updated in the Subject line text box for the campaign.

There also is an added option to provide feedback with thumbs up, or thumbs down i.e., you like the suggestion, or you don't like the suggestion.

Use Cases

Subject Line Generation allows you to: 

  • Create Subject Lines 

  • Select Tone for Subject Lines 

  • See actual predicted performance changes before you even click send 

  • Tweak your subject line copy based on the predictions 

  • Run A/B tests to validate those optimizations  


Suppose a marketer for a fashion brand is working on their email campaign to promote their new spring collection. While the email content might have already been created, the struggle to come up with a catchy customer-enticing subject line is real. Not anymore though, with ZMP.

The marketer can log into their email marketing platform and navigate to the ZMP tool. They select the Generate Subject Lines option and input the campaign history and tone selection - in this case, a playful and upbeat tone will match the spring collection. 

ZMP then uses its advanced subject line scoring model, to suggest several subject lines that are tailored to your campaign. A few options would look like: 

  • “Spring into Style with Our New Collection" 

  • "Freshen Up Your Look with Our Spring Lineup" 

  • "Get Ready for Spring with Our Latest Fashion Finds”






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