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Copy GuideApril 18, 20265 min read
The Subject Line Mistake That Kills Open Rate
Subject line mistakes.
subject lineopen ratemistakesMistakes and Fixes
| Mistake | Fix |
|---|---|
| Re: or Fwd: when it's neither | Spam filter bait. Don't fake threading. |
| All caps or excessive punctuation!!! | Looks like spam. Keep it clean. |
| Generic - Quick question, Following up | Be specific. Curiosity or observation. |
| Too long - 80+ chars | Gets cut off on mobile. Under 50 often wins. |
| Spam triggers - FREE, Act now, Limited time | Filter words. Avoid. |
Subject lines that work: subject lines. 60% opens formula: 60 opens. What looks like spam: cold email spam.
Test It
Run an A/B. Generic vs specific. Same list, same body. Specific usually wins 20-40% open lift. See how to split-test safely.
FAQ
What's the biggest killer?
Generic. "Quick question" and "Following up" get ignored. Specific beats generic every time. See subject line that got 60 opens.
Re: really hurts?
Yes. Many filters catch fake Re:. And if they open expecting a thread, they feel tricked. Bad for trust.
How to fix generic?
Add one specific thing - their company, a question, an observation. "[Company] - no website yet?"