This document analyzes subject line trends based on over 2.2 billion emails. It finds that words like "Alert" that convey urgency perform well, increasing open rates by 38.1% and click rates by 61.8%. Words like "Daily" and "Weekly" also see strong results because they establish expectations of regular communication. In contrast, words like "Newsletter", "Report", and "Learn" are trending down likely due to oversaturation of content marketing. The document also shows that promotions resonate well, with keywords like "Free Delivery", "Sale", and percentage discounts driving higher response rates.