Yesmail's Q4 email marketing report analyzes over 6.4 billion emails to identify trends and performance metrics, particularly focusing on mobile email usage and subscriber engagement. Key findings highlight a significant increase in mobile orders and revenue, with mobile devices accounting for 55% of email opens and 58% of click-throughs. The report also reveals that new subscribers show higher engagement rates compared to existing ones, emphasizing the need for targeted marketing strategies to capitalize on this segment.