Email Zeitgeist: Find Out The Most Popular Words Used In Subject Lines

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UPDATE: Litmus has been through some major updates since this post! If you’re interested in optimizing your subject lines, head on over to this Subject Line Checker post.

With over 100,000 email marketers, designers and agencies worldwide using our testing and analytics tools (we record over 250 million opens each month!), we end up with loads of data. I’ve always been fascinated by the vast amount of data that our tools generate and have been interested in sifting through it.

With last year’s launch of Scoop, a tool for better inbox management, I became even more intrigued. Scoop gives us a real-time view of what trends are popping up in marketing newsletters, triggered emails and transactional emails. I was curious — what kinds of language are people using in their emails? What does the average subject line look like? How do marketers grab the attention of their customers? How do apps and services make their transactional emails stand out?

With those questions in mind, I began my Hack Week project — the Email Zeitgeist.



The Email Zeitgeist is a free tool that peers into Scoop data and generates a snapshot of monthly trends within subject lines. It’s similar to Google Zeitgeist, which reveals what captured the world’s attention over the past year, but for email subject lines.

The Email Zeitgeist builds a “top ten” list of words that appear most frequently in email subject lines seen in Scoop. In addition, there’s even an API, so you can use the data in your own app!

See the latest data →


So what have I found using the Email Zeitgeist thus far? It seems that seasonal words are coming in at the top by month (spring, fall, etc.) and that marketing and sales language is prevalent. Also, it seems like, on average, subject line length is pretty static; not surprising since subject lines are kept succinct so they’re visible on mobile devices.

I hope you’ll find this data useful in crafting your next email subject for a campaign or transactional email. We also have an infographic full of tips and tricks for crafting the perfect subject line.


Optimize your from name, preview text, and subject line with Subject Line Checker, available in Litmus Builder.

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