What AI summaries change in practical terms
For years, marketers have treated the subject line + preview text as a paired message. You could write a slightly mysterious subject line, then use the preview text to clarify the benefit or deliver the punchline.
AI summaries disrupt that.
If a device generates its own summary, you lose control over what appears under the subject line, and that makes “clever but vague” subject lines riskier. If the AI summary is awkward, overly literal, or pulls the wrong detail, it can also reduce opens even when your email is strong.
