What does a founder learn after selling four companies, burning one to the ground, and spending years building AI agents before “AI agents” became the phrase of the moment?
Dennis Mortensen has the scars to answer that. A Danish-born, New York-based serial founder, Dennis has built and exited companies across analytics, media optimization, and AI, including X.ai, the AI scheduling assistant that raised $44 million from FirstMark and others before being acquired by Bizzabo in 2021. Today, he is building LaunchBrightly, a company automating product screenshots for help centers—a problem that sounds painfully unsexy until you realize every software company has it, every product team pays for it, and every outdated screenshot quietly creates support debt.
In this episode, Dennis joins Brian Bell for a wide-ranging masterclass on founder judgment, painful pivots, and the unglamorous infrastructure problems that make or break software companies.
In Today’s Episode We Discuss
- 00:01– Meet Dennis Mortensen
- 01:25– From IBM Dreams to Serial Founder
- 03:51– Selling His First Company During the Dot-Com Era
- 05:00– Building in Budapest and Moving to New Yor
- 07:08– Why European Founders Look West
- 09:25– The “Expensive MBA” Startup Failure
- 11:52– Why Dramatic Pivots Are Overrated
- 13:51– The Marketplace Mistake That Killed the Business
- 16:27– When the Market Is Telling You You’re Wrong
- 18:23– The Twitter Pivot and Founder Mythology
- 20:46– Why Business Model Flexibility Matters
- 22:35– Founder Bias, Persistence, and Not Dying
- 24:30– Shutting Down and Moving On
- 26:34– Building IndexTools and Real-Time Analytics
- 31:34– Why Founders Should Take M&A Calls
- 35:05– How Optionality Creates Future Exits
- 36:45– From Yahoo to Visual Revenue
- 40:01– The “List of Hate” Startup Ideation Process
- 44:57– Why Founder Focus Beats Angel Investing
- 48:43– Building Visual Revenue for Digital Publishers
- 53:44– Selling Visual Revenue to Outbrain
- 54:58– The Pain Behind X.ai
- 55:26– Market Challenge vs. Science Challenge
- 56:59– Why Scheduling Was a Worthy AI Problem
- 01:00:40– Testing X.ai with Human Assistants First
- 01:02:31– Wizard-of-Oz Testing and Scheduling Complexity
- 01:05:34– Building AI Before Modern LLMs
- 01:06:07– 47 Intents and 32 Million Labeled Data Points
- 01:10:13– Lessons from the X.ai Journey
- 01:11:14– Why Winning the Turing Test Was the Wrong Goal
- 01:14:55– When Customers Stop Being Sold and Start Buying
- 01:17:04– Introducing LaunchBrightly
- 01:17:43– Building for the Love of the Sport
- 01:19:20– Why LaunchBrightly Exists
Pull Quotes
“If you can just figure out a way to just not die, that’s probably the best way you can somehow win.”
“I have a little list of hate on my phone.”
“It’s okay to be a machine doing machine things in a machine-like way.”
Dennis’s story is not the sanitized founder mythology of perfect timing and clean wins. It is a sharper, more useful version: build, sell, fail, learn, repeat—and keep choosing problems painful enough that someone already has a human doing the work.
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