Keyword Effectiveness in 10 Common Subject Line Types

Marketers are a creative group, and it’s natural that they would want to write original, clever subject lines rather than following established formulas. However, when writing subject lines and copy, your job is to convince the reader to open your email and purchase your product, or perform some other specific action. And while there’s always room for creativity, email subject lines tend to fall into a limited number of predictable categories.

As part of our recent subject line research, we looked at some of the most common keywords used in 10 basic types of subject lines to see how they influenced performance.

The selected keywords aren’t intended to be comprehensive, but represent some of the most common keywords used in the emails we studied. Performance is reported in relation to other types of subject lines sent from the same brands.

Overall, “Urgency” subject lines performed the best, followed by “Benefit” and “Command” subject lines. Keywords commonly found in “Clickbait” headlines hope to take advantage of the curiosity factor—and while these may work on social networks and news sites, they are far less successful in email subject lines.

image_2 (1)

image_3 (1)

image_4 (1)

Want to find out more about the unique influence of email subject lines, and how to create subject lines that convert? Check out The Art and Science of Effective Subject Lines.

minute read

Popular stories



BriteVerify email verification ensures that an email address actually exists in real-time


The #1 global data quality tool used by thousands of Salesforce admins


Insights and deliverability guidance from the only all-in-one email marketing solution

GridBuddy Cloud

Transform how you interact with your data through the versatility of grids.

Return Path

World-class deliverability applications to optimize email marketing programs

Trust Assessments

A revolutionary new solution for assessing Salesforce data quality


Validity for Email

Increase inbox placement and maximize subscriber reach with clean and actionable data

Validity for Data Management

Simplify data management with solutions that improve data quality and increase CRM adoption

Validity for Sales Productivity

Give your sales team back hours per day with tools designed to increase productivity and mitigate pipeline risks in real-time