The warning signs that should end a startup idea

The Founders work group separates real kill signals from low signups and investor doubt.

Updated October 13, 2026

Drop or change an idea when the people who have the problem can find it, try the full version, and still have no reason to come back.

Nobody comes back. Ben Silbermann would drop or change an idea if repeated conversations and improvements leave no small group that chooses to use it again. Low signups alone would have sent Pinterest away from a real audience at about 3,000 accounts.
Judge the full claim. Coda's first customer went from six daily users to zero after seeing mostly the tables. Shishir Mehrotra counts repeated rejection by customers who tried the full idea as a kill signal, and feedback on a slice as a list of what to fix.
The customer stays vague. Emmett Shear would stop a team that keeps switching products while describing its customer as "everyone who uses a calendar," as Kiko did, and choose one customer first. Investor rejection is a weaker signal: 40 VCs turned down Twitch while people were using it.
The business doesn't hold up. Ivan Zhao would ask who pays and why, and whether the cost of delivering the product leaves room to keep serving them. Reid Hoffman would reconsider when the next plan has worse odds than the first, or when funding forces a business model customers can't back up, as at SocialNet.

Group chat with Emmett, Ben, Ivan, Reid, Shishir — the Founders work group

Question:

Which warning signs should make a founder drop an idea?

Ben SilbermannFounder and Chairman of Pinterest. Founder of How We Feel

I would look for a missing reason to come back. With our shopping app before Pinterest, we kept adding features and still couldn't name one thing the product did especially well. My test now is whether a founder can ship one experience worthy of someone's time, then find people who choose to use it again. If repeated conversations and improvements still leave you unable to find even a small group that cares about that experience, I would drop or change the idea.

startuparchive

Pinterest gives an important check on that test. After roughly four months we had only about 3,000 accounts, yet a few people really loved making collections. We met those users and found more people like them. Weak signups alone would have sent us away from an idea with a real early audience.

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Shishir MehrotraCEO of Superhuman (formerly Grammarly). Co-founder of Coda and former Chief Product Officer of YouTube

I think a founder should reconsider an idea when its central assumption fails a hard test. Ask what everyone else assumes about the market, what you believe instead, and what has kept others from building it. If the difference amounts to a missing font or line-spacing option, there may be a feature to build, but little reason for a new company. For Coda, our bigger claim was that the boundary between documents and apps was artificial; we believed web-based tools had removed a file-format barrier that held earlier products back.

Apple Podcasts

Then watch behavior. Our first customer's daily users went from six to zero, and the team said they would quit if their CEO made them keep using Coda. That was a severe warning about the product. They also gave us a specific list of changes and still believed in the goal, so we kept working. Later, a customer asked to expand Coda to another team. For a team product, repeated abandonment after you address specific problems, with nobody asking to bring colleagues in, would make me question whether the idea solves a problem people care enough to change their work for.

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Ben SilbermannFounder and Chairman of Pinterest. Founder of How We Feel

Shishir's example makes the customer conversation more useful than a bare usage count. I would ask the people who stopped using the product what they hoped to do and where the experience broke, then ask the few who stayed what they actually value. At Pinterest, the small group who loved making collections helped us see that reaching and connecting with similar people was a problem we could work on. We held meetups and asked bloggers to introduce the service to their readers.

forbes If the people who stay cannot describe a specific use worth sharing with someone else, another round of outreach has little to build on.

Ivan ZhaoFounder of Notion

Our first version of Notion exposed a warning sign: the people we hoped to reach had a different job to do. We spent more than two years making it easier for people to build their own software. Friends and investors tried it, and the idea failed to resonate. Most people had a report due or a task to finish; they wanted a tool they could use right away. We changed the product into familiar productivity software while keeping the underlying ability to make your own tools.

Apple Podcasts

A second warning sign is a technical foundation that prevents you from fixing what people need. We had chosen web components, found the foundation too unstable to debug reliably, and rebuilt. I separate three decisions: stop selling the current product, replace the implementation, or give up on the underlying need. Our evidence called for the first two.

Apple Podcasts

Emmett ShearCEO of Softmax. Founder of Justin.tv and former CEO of Twitch

Kiko taught me to watch for a team that responds to weak usage by changing products while staying vague about whom it serves. Kiko got a TechCrunch feature, grew a little, and then stopped. We launched a family network that got 12 users and quit that experiment. The deeper failure was that we described Kiko’s customer as “everyone who uses a calendar.” Each new project improved our execution, yet the work never accumulated around one customer. I’d stop that cycle and choose a specific customer before building the next product.

Spotify+1

I’d treat investor rejection separately. Forty VCs turned down Twitch because gaming seemed too small; we had evidence of people actually using it, so their market-size judgment was a poor kill signal.

Apple Podcasts

Shishir MehrotraCEO of Superhuman (formerly Grammarly). Co-founder of Coda and former Chief Product Officer of YouTube

Ben's point about asking the people who stopped is right, and I would ask which part of the intended product they actually tried. Our first Coda customer gave us about 30 specific requests after the entire six-person team stopped using it. We took the feedback seriously, yet we did not build that list first. They had mainly seen our tables; the document, forms, and layouts that were central to the product were still missing. We kept building those pieces, and it took another two or three years to work through their list.

Apple Podcasts

A useful kill signal is repeated rejection by customers who have actually experienced the full claim behind the idea. Feedback on an incomplete slice can tell you what to fix, but it can give you the wrong answer about whether the idea itself works.

Reid HoffmanCo-founder of LinkedIn, Inflection AI and Manas AI. Partner at Greylock

Ben's small group of committed Pinterest users is the right guard against quitting on low signups alone. Track whether each serious iteration improves your odds of success. When the next version of the plan has worse odds than the first, given what you have learned about customers and the market, I would consider a major pivot.

Spotify

SocialNet gave me a different warning sign: financing can keep an idea alive after the founder has lost confidence in its business model. We accepted the only funding offer we had and changed our model to serve media partners, even though we had little sense of how that would work. Roughly two years in, I told the board I no longer believed in that model and helped with the transition. If a funding condition forces an untested business model that you cannot make credible through customer evidence, reconsider the idea before the new capital locks you into it.

Spotify

Ivan ZhaoFounder of Notion

Another kill test comes after people start using the product: can the value support a business? Early at Notion, I learned that a product people like still needs a way to reach people, a reason for them to pay, and unit economics that let the team keep building. I would ask a founder to name who pays and why, then check whether the cost of delivering the product leaves room to keep serving them. If repeated attempts to find a workable answer fail, the current business idea needs to change even if the product has devoted users.

Apple Podcasts

Emmett ShearCEO of Softmax. Founder of Justin.tv and former CEO of Twitch

Shishir’s distinction about testing the full claim matters. When we had three months of runway to choose between gaming on Justin.tv and another project, we set a bar for gaming of roughly 20 to 25% monthly usage growth. Gaming grew 30% a month for all three months. A founder can set a time-bound usage bar before the test, then decide against the current direction if it misses. The number should fit the business; the useful part is making a decision rule while the team still has room to act.

Spotify

Shishir MehrotraCEO of Superhuman (formerly Grammarly). Co-founder of Coda and former Chief Product Officer of YouTube

A survey can obscure the warning sign if you treat one score as a verdict. At Coda, we saw high scores when we asked how disappointed people would be if they lost the product, alongside low scores when we asked whether they would recommend it. In the same interview I described Superhuman seeing nearly the reverse pattern.

Apple Podcasts

I would ask both questions, then investigate the gap. People who would miss a product but hesitate to recommend it may be pointing to friction in using or sharing it. If the people doing the target job would barely miss it, that is stronger evidence against the underlying idea.

Ben SilbermannFounder and Chairman of Pinterest. Founder of How We Feel

Ivan's point about the intended user matches a mistake I nearly made with Pinterest. Friends in tech were polite but didn't use it. The people who kept making boards were using them for ordinary plans, like a home or a meal, so we went to the bloggers those people already followed and invited their readers in.

YouTube Before treating silence as a kill signal, I would check whether the people who actually have the problem can find the product and use it. If they can, and the one thing you built still gives them no reason to return, I would change the idea.

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Frequently Asked Questions

What are the signs of product-market fit?
A small group who would be upset to lose the product, then growth you can explain, from users who look like the market you want to win. Fit rarely arrives as one moment.
How is early traction different from product-market fit?
Traction responds to a launch, press or founder effort and fades when that stops. Fit keeps compounding through the product's own loop, and the love repeats with strangers who match the first fans.
What should you do when product-market fit isn't coming?
Make the next attempt a bounded test with a target and a deadline the cash can cover, check that the test was fair, and change course on a miss. With no promising group or runway left, return the capital.
How do you pressure-test a startup idea?
Set a behavior bar before the team gets attached, put an early version into someone's real work, and write down the ways the company could fail even if early users love it.
How do founders find a problem worth solving?
Start from a problem you will care about for years, find people whose behavior shows they have it too, and know why you can make progress where others see risk.
What should a first-time founder do first?
Start, choose a cofounder with care and get something in front of strangers early. The group splits on whether research or a rough product comes first.
How do you size a market before building?
Start from a behavior people already have, ask what has kept anyone from winning the market, and let growth or repeat use tell you its size.
How does a startup stand out in a crowded market?
Pick one experience people return to, start with the people whose choice brings everyone else, and check whether users come back for a second job.
Where can an AI startup win against the model companies?
Around what takes sustained work to copy: a group's accumulated taste, a team's workflow, trust between people or a creator's audience.
How do you validate an idea with customers?
Go out to learn, ship one thing worth a stranger's time, watch who comes back on their own and then ask them why.
How do you choose a consumer products category?
Look for a need people already recognize, evidence that they act on it, and unit economics that work across the whole purchase cycle.

All starting a startup questions →

Frequently Asked Questions

The warning signs that should end a startup idea

Founders

Frequently Asked Questions

What are the signs of product-market fit?

How is early traction different from product-market fit?

What should you do when product-market fit isn't coming?

How do you pressure-test a startup idea?

How do founders find a problem worth solving?

What should a first-time founder do first?

How do you size a market before building?

How does a startup stand out in a crowded market?

Where can an AI startup win against the model companies?

How do you validate an idea with customers?

How do you choose a consumer products category?

Your ideas, super powered.

The warning signs that should end a startup idea

Founders

Frequently Asked Questions

What are the signs of product-market fit?

How is early traction different from product-market fit?

What should you do when product-market fit isn't coming?

How do you pressure-test a startup idea?

How do founders find a problem worth solving?

What should a first-time founder do first?

How do you size a market before building?

How does a startup stand out in a crowded market?

Where can an AI startup win against the model companies?

How do you validate an idea with customers?

How do you choose a consumer products category?

Your ideas, super powered.