AI tools in email clients are generating summaries that replace marketer-written preheaders. These tools pull content from the first 150 characters of 'live text' (HTML text) in the email's body, making this opening content critically important for controlling the message in the inbox.
The AI tools creating email summaries do not scan images for content, and critically, they also ignore alt-text. This means any vital information for the summary, such as an offer or event detail, must be actual 'live text' at the very top of your email to be recognized and displayed in the inbox preview.
A predicted rapid shift will see half of all email preheaders being AI-generated, not marketer-written. This necessitates an immediate strategic change from crafting the perfect preheader to optimizing the first 150 characters of the email body, as this content will increasingly become the de facto preheader.
To optimize for AI summaries, marketers must shift away from visually slick, image-heavy headers. The focus is now on raw, scannable text content at the top of an email. This represents a strategic regression to simpler email structures, prioritizing AI readability over complex visual design.