Your subject line is a large part of what makes or breaks an email campaign. It's the first thing a subscriber sees, and it decides whether they open, ignore, or mark you as spam.
Here are three common subject line mistakes worth fixing before your next send.
Subject Line Mistake 1: Leaving it blank
35% of email subscribers open an email based on the subject line alone. Leave that field empty and you've already lost over a third of your audience before they've seen a single word of your content. The rest will just be confused.
TouchBasePro won't let you send with a blank subject line. That's not us being heavy-handed, it's a guardrail we built in because blank subject lines hurt campaigns, and we've seen it happen enough times to make it a hard stop.
Subject Line Mistake 2: RE: what?
69% of email recipients will report an email as spam based on the subject line alone. That's a high bar to clear, and a fake conversation thread will clear it fast.
Spammers have long used "RE:" at the start of a subject line to make it look like you're continuing an exchange. There is no exchange. Whether the email is a legitimate campaign or a link to a dodgy site, the tactic fools nobody and flags you immediately. Drop the RE: prefix. Your subscribers will thank you.
Subject Line Mistake 3: Subject Line To Be Advised
This one is more common than it should be. You're setting up a campaign, you're not sure what the subject line will be yet, so you type something like "Subject Line TBA" as a reminder and move on. Then you forget to go back and change it. Your subscribers receive an email with exactly that as the subject.
The fix is simple: test your campaign before you send it. Check every field, not just the body copy. A pre-send checklist, and a second pair of eyes if you have one, will catch this before it becomes an embarrassing reply-all story. If you want a starting point, our post on checking yourself before you wreck yourself walks through the full pre-send process.
Write a subject line worth opening
Three mistakes, all avoidable with a bit of process. Once you've got the basics right, it's worth looking at what actually works. Our list of 10 success words for subject lines is a good next step, and the 5 subject line formulas that increase open rates gives you a repeatable structure to work from.
Frequently asked questions
- What happens if I send an email with a blank subject line?
- You lose the 35% of subscribers who decide whether to open based on the subject line alone. The rest are likely to ignore it. TouchBasePro blocks sends with blank subject lines to prevent this.
- Why is adding RE: to a subject line a problem?
- It mimics a reply to an existing conversation that doesn't exist. Subscribers recognise this as a spam tactic, and 69% of recipients will report an email as spam based on the subject line alone. Avoid it entirely.
- How do I avoid sending an email with placeholder text in the subject line?
- Build a pre-send checklist that includes every field, not just the body copy. Send a test to yourself or a colleague before the campaign goes live. Catching it at the test stage costs nothing. Catching it after costs your reputation.