Why Plain Subject Lines Get Opened and Clicked
I had AI go through 90 days of emails on my HobbyScool list, about 45,000 subscribers. Open rates barely changed from one subject line to the next, but click rates changed a lot, and the winners were plain subject lines that named a specific project or number. A newsletter software CEO said the same thing at a publishing conference last month: tell people what's inside and skip the tricks.
A lot of creators spend more time on the subject line than on the email itself, writing five versions and trying to make one of them clever.
So when I recorded my workshop for the AI Newsletter Summit this week, I used my own HobbyScool list for the demo. I connected Claude to my Kit account and asked it to show me where I was losing people and what my list actually responds to. The subject line results were really clear.
What a newsletter CEO said works right now.
Before I get to my numbers, here's what made me want to write this. At Press Gazette's Future of Media Technology Conference in September, Christopher Sopher, the CEO of the newsletter platform Letterhead, said the subject lines that perform best for his customers are the boring ones. You can read the Press Gazette write-up here.
His point was that the value is inside the email. When the subject line or preview text tells people what's in there, the people who want it click. He said he hasn't seen any tricks that beat that.
Sopher works with big news publishers, and my list is crafters. My own data showed the same thing anyway.
What 90 days of my emails showed
Claude pulled 39 emails that went to my full HobbyScool list over the last 90 days. That included my Sunday newsletters, free summit invites, a craft challenge and a promotion for our Craft and Create Club membership.
The open rates only moved between 51.4% and 59.3%. That means the subject line didn't change much about whether people opened. The click rates went from 0.91% to 4.88%, which is a big spread, so what's inside the email and what the subject line promises made a much bigger difference.
One more thing about opens. Apple Mail counts some emails as opened even when the person never looked at them, so open rates are a little inflated for everyone. Clicks are the better number to watch.
The subject lines that did best
These had the highest open rates on the full list, and they were also the best click rates:
- "12 free summits, one big schedule reveal" got a 59.3% open rate and 4.63% clicks
- "Your paper scraps are already a book" got 58.4% opens and 3.27% clicks
- "You don't have to watch all 33" got 58.4% opens and 4.88% clicks
- "It starts today: Tiny Zine Play with Consie" got 58.2% opens and 3.22% clicks
- "Ten weeks of fall decorations" got 58.1% opens and 3.21% clicks
- "The craft with no loom, no pattern, and one knot" got 57.9% opens and 4.36% clicks
Every one of those names something people can make or a number they can picture. None of them are clever. They just say what's in the email.
On HobbyScool, the clearest subject lines were about the thing people could make. When the email named the project, people opened it and clicked through to see it.
The subject lines that didn't do as well
The lowest open rate of the whole 90 days was a sales email called "One payment, no renewals." It got 51.4% opens and 0.91% clicks. It's a true statement about the offer, but it doesn't tell a crafter what they'll get to make.
I also ran two craft challenges during that time. The challenge emails that named the project, like "Tomorrow: turn your junk mail into art," got 2.84% and 3.22% clicks. The challenge emails that led with the teacher's name got between 0.92% and 1.64%. That second challenge ran during a promotion, so it's not a perfect comparison, but the gap is big enough that I'm paying attention to it.
And the summit invites that opened with a business problem, like "You opened the Etsy shop. Then you waited.," got some of the lowest clicks of all the invites, around 1.5%.
How I'm changing my subject lines.
I'm working on our holiday emails for HobbyScool right now, so I had Claude check those drafts against these results. Here's what the numbers point to:
- Name the project. If the email is about a workshop, the subject line says what people will make.
- Use a real number when there is one. "12 free summits" and "Ten weeks of fall decorations" both did well.
- Lead sales emails with what they get. The price and the payment terms go in the email, and the subject line talks about the projects.
- Watch clicks first. When I compare two emails, the click rate is the number I trust.
Your list might respond to something different, and that's the whole reason to look. A business coach's list might click on a specific result or a specific number of clients. The pattern I'd test first is the same one, though. Say plainly what's in the email.
Polls and reply prompts work too, when you do them every time
Sopher talked about one more thing that's working for publishers, and it's interactivity. That means polls, quizzes, and asking readers to hit reply and tell you something.
Someone asked him if those are gimmicks, and his answer was that it depends on whether they're a regular part of your newsletter. When readers expect a poll every week, it does well. When you try one every couple of months, it takes a while to see results.
This fits right into my Mini Magazine Method, which is how I teach people to set up their newsletter with the same few sections every issue. A standing poll or a "hit reply and tell me" section can be one of those sections, and it gets better results than tossing one in now and then.
How to run this check on your own list
You don't need to do this by hand. If you use Kit, you can connect it to Claude and ask something like this:
Pull every broadcast I sent to my full list in the last 90 days with the subject line, open rate, click rate and unsubscribe rate. Group them by type of email and tell me which subject lines got the most opens and clicks, and what they have in common.
When I first ran my audit, Claude made a few assumptions about my list that weren't right, like treating my planned list cleanup as people leaving on their own. So I told it to ask me questions one at a time, and the second version was a lot more useful. Expect to do that with your own data too.
See the full demo
My recorded session at the AI Newsletter Summit, Find Out Where You're Losing Subscribers With AI, walks through this exact audit inside my Kit account. There's also a live Kit session on Tuesday, October 27 where I share my AI email playbook. The summit is free, and the recorded workshops stay open until Friday morning of summit week.
Tomorrow's post is about AI inbox summaries, and which kinds of newsletters they're going to hurt.
Watch me run this audit at the AI Newsletter Summit
My session Find Out Where You're Losing Subscribers With AI shows the whole demo inside my Kit account. Registration is free.
Save your seat →Frequently asked.
What kind of email subject lines get the most opens?
Plain ones that tell people what's inside the email. On my HobbyScool list, subject lines that named a specific project or a number, like "You don't have to watch all 33," got the highest open and click rates over 90 days.
Should I judge subject lines by open rate or click rate?
Look at both, but lean on clicks. On my list, open rates only moved between about 51% and 59%, while click rates ranged from under 1% to almost 5%. Apple Mail also counts some opens automatically, which makes open rates less reliable.
Can AI analyze my email subject lines?
Yes. I connected Claude to my Kit account and asked it to pull the subject lines, open rates and click rates for 90 days of emails and tell me what my list responds to. It sorted them by type and showed me the patterns.
Are polls and reply prompts in newsletters a gimmick?
Not when they're a regular part of your newsletter. Letterhead's CEO said they perform well when readers expect them as part of the format, and take longer to work when you only try them once in a while.
What should a sales email subject line say?
Name the thing people get. On my list, sales emails that only talked about the deal or the payment terms had the lowest opens and clicks, while emails that named a project people could make did much better.
Dr. Destini Copp helps digital product creators build sustainable, systems-based businesses through the Creator Growth Flywheel framework. She's the founder of Creator's MBA and HobbyScool, and has been teaching online business strategy for over a decade. Learn more →
