Almost all cold email advice is written by senders, for senders. Subject line formulas, follow-up cadences, personalization tokens, domain setups. Very little of it asks the people on the other end what they actually do with the email when it lands.
So we went and read what they say when no salesperson is in the room: public threads on Hacker News where founders, CEOs, and engineers talk about the cold email they receive. The pattern is uncomfortable for anyone who sends cold email for a living.
The tactics the cold email playbook recommends are the same things buyers now use to filter it out.
One caveat up front: Hacker News readers are harsher on cold email than the average buyer. But they're also exactly the founders and technical leaders a lot of B2B companies are trying to reach. If your email can't get past them, that's worth knowing.
Six tricks that turned into tells
A “tell” is a habit that gives you away. Each of these started as genuine advice, spread through courses and tools, and is now something buyers spot in a second.
1. The “internal-feeling” subject line
The advice: write subject lines like “Quick question” so the email feels like it came from a colleague.
What the recipient sees:
“I immediately delete any email with a subject line like ‘quick question’. It does not give me any reason to think I will get any value from it.” Source
“I perceive such subject lines as an indicator that an email is probably an outright scam. All senders receive a silent and permanent block from me without exception.” Source
A subject line that pretends to be internal works until the reader notices it isn't. After that, it doesn't just fail. It makes you look like you were trying to trick them.
2. The AI icebreaker
The advice: open with something personal you found on their profile, then pivot to your offer.
“They all follow the same formula: try to break [the] ice with something funny about somewhere I took a photo recently, then segue into what I do for work, then offer to help me do it better… It's such an obviously repetitive recipe.” Source
Another commenter quoted the template line itself, “I came across [Company] and was impressed by the work you're doing,” and added: “It's a terrible cold email, I get so many of these every week.” (source). We've written before about why relevance beats personalization. This is the buyer's side of the same story.
3. The look-alike sending domain
The advice: never send cold email from your main domain. Buy variations of it and send from those.
“Registering lots of domains (launchmyapp.com, trymyapp.com, myapp.info, gomyapp.biz, etc.)… Now pretty much every domain that isn't myapp.com looks like a spammer's domain to me.” Source
This one is awkward for us, because protecting your main domain is still the right call, and we do it for every client. The lesson isn't to stop. It's that a secondary domain has to look like a real part of your company: a website that loads, the same brand, a real person behind the address. A bare “try-” domain that leads nowhere is now a tell in itself.
4. The bump
The advice: follow up, and keep the thread on top of their inbox.
“I've found very few people actually enjoy getting ‘bumping this to the top of your inbox’ from cold email senders.” Source
Following up isn't the problem. Following up with nothing new is. If your second email doesn't add a reason to reply that the first one didn't have, it's just a louder version of something they already ignored.
5. The guilt breakup
The advice: end the sequence with a “breakup” email, or ask them to forward you to the right person.
“‘I guess you are not the person who can make this decision. Could you forward me to…’ No, I am not doing your job for you.” Source
Another described sequences that “beg ‘I know you're probably sick of hearing from me, but I'll give it one last try’ until they follow up again” (source). Guilt is a tactic. Buyers can tell, and it's the last thing they remember about you.
6. The 30-minute ask
The advice: keep it short and ask for a call.
Short is fine. Asking for half an hour of someone's week before giving them a reason isn't. One reader, praising an unusually useful cold email, put it this way: “Much better than the ‘can I get on your calendar for 30 minutes’ with little other context.” (source)
Why every trick becomes a tell
Each of these tactics worked once, because it was rare. Then it was written up, taught in a course, built into a tool, and sent by thousands of people at once. Buyers saw it fifty times a week, learned the pattern, and the tactic flipped from a way in to a filter.
AI sped the cycle up dramatically. Personalization used to work because it was expensive: a hand-written, researched email proved someone had spent time on you. That proof is gone.
“AI has made ‘hand-written’ style emails incredibly cheap to forge at scale.” Source
“If an AI generates cold emails, there's no real time spent, making personalization feel deceptive.” Source
Economists call this a costly signal: a signal is only believable if it's expensive to fake. When personalization became free, it stopped meaning anything. Worse, it started to feel like a lie.
A cold email signal only works if it's expensive to fake.
What still gets through
The same people who block “quick question” on sight describe, quite specifically, the emails they do answer. Every one of them involves something the sender couldn't fake at scale.
Proof you engaged with their actual work
“I get dozens of cold emails and LI messages from sales/ recruiting a week. Only about one per year writes ‘I read your blog and liked your point about xyz.’ I always take that call.” Source
Note the difference from the AI icebreaker. “Loved your post!” is a compliment anyone can generate. A specific point from their writing, and what you think about it, takes reading.
Being a customer first
“It's nice to write nice things about the things that person has done… But it's nicer to write about things they've created and you paid money for.” Source
Money spent is about the most expensive signal there is. It's also impossible to fake at volume.
An obvious link to one of their top problems
“I often reply to cold emails, but honestly, with 90% of them, I can't really tell if they will solve one of my top 3 problems.” Source
That's not a complaint about tone or length. It's a complaint about clarity. If the problem you solve isn't obvious in the first two lines, most busy buyers won't do the work of figuring it out.
Work done before asking
An audit, a teardown, a list, an analysis of their actual situation. Real work done upfront is the modern version of the hand-written letter: it costs the sender something, so it can't be sprayed at 10,000 people. That's why we build every campaign around an offer worth replying to rather than a clever opener.
| Cheap to fake (now a tell) | Expensive to fake (still works) |
|---|---|
| “Quick question” subject line | A subject that names their actual problem |
| A compliment about their post or photo | A specific point from their work, and your view on it |
| “Bumping this to the top” | A follow-up that adds something new |
| “Are you the right person?” | Research that found the right person first |
| “30 minutes this week?” | Something useful delivered before any ask |
| A bare look-alike domain | A sending domain that's clearly, visibly your company |
The test that outlasts every trick
One commenter offered a rule we now use on every sequence we write:
“If everyone did this would it still work… If you are sending cold emails to people you know will be interested, that's fine. There is no upper bound on how many actually useful opportunities people are willing to receive.” Source
Run your current sequence through it. If every sender used your subject line, would it still get opened? If every sender used your opener, would it still feel personal? Tricks fail this test by definition: they work only while few people use them. A useful offer, sent to someone who has the problem, passes it no matter how many others are emailing.
A two-minute self-audit
Before your next send, check your sequence for these tells:
- A subject line pretending to be internal or personal.
- A first line that compliments instead of naming a problem.
- A sending domain with no website or brand behind it.
- A follow-up that only says “bumping this.”
- A breakup email built on guilt, or a request to be forwarded.
- A request for their time before you've given them anything.
If you find more than two, the problem probably isn't your copywriting. It's that your emails look like everyone else's. Send us one and we'll tear it down for free, from the perspective of the person deciding whether to delete it.