Click bait
Subject lines or copy that promise more than the body delivers — short-term clicks, long-term trust erosion.
Click bait, in email, is the practice of using subject lines or preheaders that overpromise relative to the body content — creating curiosity, urgency, or social-proof signals that the email doesn't pay off. Examples: "You won't believe what we shipped" (body: a minor patch note), "Bad news inside" (body: a sale).
Click bait works in the short term and erodes trust in the long term. The first send shows a spike in opens; subsequent sends from the same sender show lower opens as recipients learn that the subject lines aren't reliable signals. Many ESPs now down-rank senders whose engagement metrics decay over time — a structural disincentive against click bait.
The honest version of curiosity-driven subject lines is the curiosity gap that pays off in the first 30 words of the body. Curiosity is fine; bait isn't. The distinction is whether opening the email leaves the reader feeling rewarded or tricked.