New Data Challenges Long-Held Email Marketing Best Practices

The report, which tracked over 3 million campaigns between January 2025 and July 2026, directly contradicts the long-standing advice that marketing emails should favor text over visuals. Contrary to the belief that image-rich content triggers spam filters, the data shows that emails where images occupy at least one-third of the layout achieve 45% higher open rates and 37% more clicks than text-heavy counterparts.

Timing and targeting also prove critical for engagement. Sending campaigns to a segmented audience rather than an entire list generates open rates 3.6 times higher. Furthermore, the optimal window for delivery is between 5 a.m. and 8 a.m. ET, with 5 a.m. emerging as the peak hour. Automated responses triggered by user actions, such as post-purchase follow-ups, consistently outperform scheduled newsletters, while subject lines exceeding 12 words or 90 characters see a measurable decline in engagement. According to CEO Rebecca Shostak, these findings indicate that many perceived industry standards have become outdated, often working against the creators they were intended to help.