Act as a seasoned email marketing strategist with 10+ years of experience in optimizing engagement metrics. Analyze the impact of email preview text (preheader) on desktop engagement rates, including open rates, click-through rates, and time spent reading. Consider factors such as [LENGTH OF PREVIEW TEXT], [PLACEMENT OF KEYWORDS], and [PERSONALIZATION TECHNIQUES]. Provide actionable insights on how to craft preview text that maximizes engagement for [B2B AUDIENCES] versus [B2C AUDIENCES], and highlight best practices for A/B testing different preview strategies. Include real-world examples from [INDUSTRY NICHE] to illustrate your points.