Airbnb

OpenAI

Airbnb

Airbnb is a two-sided marketplace. Hosts list their homes, apartments, treehouses, or whatever else they've got.

Guests book and pay through the platform. Airbnb takes a cut from both sides — roughly 3% from hosts and up to 14% from guests as a service fee.

That's it. They don't own a single property.

They just built the world's largest hotel chain without owning a single bed.

OpenAI

OpenAI makes money primarily through API access and subscriptions. The API charges developers per token (roughly per word) for using GPT models in their applications.

ChatGPT Plus costs $20/month for individual users, ChatGPT Team is $25-30/user/month, and ChatGPT Enterprise is custom-priced. Microsoft pays OpenAI licensing fees and also resells OpenAI models through Azure OpenAI Service.

OpenAI's annualised revenue ran past $13 billion during 2025 and kept climbing from there, which is the kind of growth curve that normally only exists in a pitch deck.

Airbnb

In 2007, Brian Chesky and Joe Gebbia were two Rhode Island School of Design grads living in San Francisco and struggling to make rent. A big design conference was coming to town and every hotel was booked solid.

They bought three air mattresses, put up a simple website called AirBed & Breakfast, and charged $80 a night including a homemade breakfast. Three strangers actually showed up.

That was it — the entire origin story of a $75 billion company is three air mattresses and desperation.

They recruited Nathan Blecharczyk, a Harvard-trained engineer Joe knew, to build the real website. But nobody wanted to fund them.

They applied to 15 investors and got rejected by every single one. To keep the company alive during the 2008 election, they designed limited-edition cereal boxes — Obama O's and Cap'n McCain's — and hand-assembled 500 of each.

They sold the Obama O's for $40 a box and made $30,000. That cereal money literally kept Airbnb from dying.

Paul Graham at Y Combinator finally let them into the Winter 2009 batch — reportedly because the cereal stunt proved they were "cockroaches" who would never die. YC invested $20,000.

Within a few months, Sequoia Capital led a $600,000 seed round. The rest is history.

OpenAI

OpenAI was founded in December 2015 as a nonprofit AI research lab. The founding donors — including Elon Musk, Sam Altman, Peter Thiel, Reid Hoffman, and Jessica Livingston — pledged $1 billion with a mission to build artificial general intelligence (AGI) that would benefit all of humanity.

The idea was that AI was too important and too dangerous to leave in the hands of Google alone.

Sam Altman became chairman while Greg Brockman (former CTO of Stripe) became president. Ilya Sutskever, one of the most respected AI researchers alive, left Google Brain to become chief scientist.

The early team was stacked with world-class researchers who published their work openly — hence "Open" AI.

But AI research turned out to be staggeringly expensive. Training large models required millions of dollars in compute.

In 2019, OpenAI created a "capped-profit" subsidiary — investors could earn up to 100x their money, but profits beyond that would flow to the nonprofit. Microsoft invested $1 billion.

The mission was still to save humanity. The method now involved making a lot of money first.

Airbnb

The early growth was pure hustle. Chesky and Gebbia flew to New York — their biggest market — and went door to door visiting hosts.

They noticed the listings with bad photos got no bookings. So they offered free professional photography to every host.

Bookings exploded. That single move — better photos — was probably worth more than any ad campaign they ever ran.

They also pulled one of the most legendary growth hacks in startup history. They reverse-engineered Craigslist's posting system so that Airbnb hosts could cross-post their listings to Craigslist with one click.

Craigslist had millions of people looking for rentals. Airbnb had none.

The hack funneled Craigslist's traffic straight into Airbnb. It was borderline shady and absolutely brilliant.

Word of mouth did the rest. Every guest who had a great stay told their friends.

Every host who made easy money told their neighbors. The product sold itself because both sides benefited immediately.

By 2015, Airbnb had more listings than the top five hotel chains combined.

OpenAI

ChatGPT's launch in November 2022 was the growth strategy — it just wasn't planned that way. The team expected a modest research preview.

Instead, ChatGPT hit 1 million users in 5 days and 100 million monthly active users in 2 months, making it the fastest-growing consumer application in history. The product went viral because it felt like magic — for the first time, anyone could have a natural conversation with a machine that seemed to understand them.

The Microsoft partnership provided distribution at massive scale. Microsoft integrated OpenAI models into Bing, Office 365 (Copilot), GitHub (Copilot), and Azure.

Overnight, hundreds of millions of Microsoft users had access to OpenAI technology. Microsoft's $13 billion investment was the largest AI bet in history and gave OpenAI nearly unlimited compute.

The API created an ecosystem. Thousands of startups built products on top of OpenAI's models — from customer service bots to coding assistants to content generators.

Each API customer locked themselves into OpenAI's ecosystem, creating switching costs and recurring revenue.

Airbnb

Regulation. Full stop.

Cities around the world have gone to war with Airbnb. New York, Barcelona, Amsterdam, Paris, Berlin — all have passed laws restricting or outright banning short-term rentals.

The hotel lobby has spent hundreds of millions fighting Airbnb at every level of government. In New York City, a 2023 law essentially banned most Airbnb listings overnight.

Then COVID hit. In March 2020, Airbnb's business dropped 80% in eight weeks.

Chesky had to lay off 1,900 employees — 25% of the company — in a single memo that became famous for how honest it was. He gave everyone 14 weeks of severance and a year of health insurance.

The company burned through its IPO plans and took on $2 billion in emergency debt at brutal interest rates.

But here's the thing — COVID also saved them. People stopped wanting hotel lobbies and started wanting isolated cabins and rural homes.

Airbnb's bookings came roaring back by summer 2020, and the rural/unique stays trend became permanent. They IPO'd in December 2020 at a valuation that stunned everyone.

OpenAI

The board crisis of November 2023 nearly destroyed the company. The nonprofit board fired Sam Altman as CEO on a Friday, citing a loss of confidence.

Within 48 hours, 95% of employees threatened to quit and follow Altman to Microsoft. By Tuesday, Altman was reinstated and the board was restructured.

The incident exposed the fundamental tension between OpenAI's nonprofit governance and its for-profit ambitions — a tension it finally addressed in late 2025 by restructuring the business as a public benefit corporation sitting under the original nonprofit.

The cost of training frontier models is eye-watering. Each new GPT generation costs hundreds of millions to train.

OpenAI is reportedly spending over $7 billion annually on compute. The company is burning through cash faster than almost any startup in history, which is why it keeps raising at higher and higher valuations.

If revenue growth slows before costs stabilize, the math gets ugly.

Safety concerns are not going away. Multiple prominent researchers have left OpenAI over disagreements about the pace of development versus safety research.

Ilya Sutskever, the chief scientist who was central to the board's decision to fire Altman, left in 2024 to start a safety-focused AI lab. The public debate about whether OpenAI is moving too fast — and whether its safety commitments are genuine — grows louder with every capability improvement.

Airbnb

Airbnb Stays is the core product — book someone's home instead of a hotel. Airbnb Experiences lets you book local activities run by hosts, like cooking classes in Rome or surf lessons in Bali.

Airbnb Luxe is the ultra-premium tier — think private islands, castles, and villas with dedicated concierge service. Airbnb Plus, an inspected-homes tier, was wound down in 2023 after proving too costly to verify at scale.

Categories (launched 2022) lets you browse by vibe — treehouses, lakefront, tiny homes, mansions — instead of just searching by location.

OpenAI

ChatGPT is the consumer chatbot — the product that made AI mainstream overnight. The flagship GPT models are multimodal, handling text, images, and audio in one system.

The OpenAI API lets developers integrate GPT into any application. DALL-E generates images from text descriptions.

Whisper transcribes and translates audio. Sora generates videos from text prompts.

GPT Store lets users create and share custom GPT agents. ChatGPT Enterprise gives businesses a private, secure version of ChatGPT with admin controls and no data training.

Airbnb

Y Combinator, Sequoia Capital, Andreessen Horowitz, Greylock Partners, Founders Fund, General Atlantic, Jeff Bezos (personal investment)

OpenAI

Microsoft ($13B), Thrive Capital, Khosla Ventures, Sequoia Capital, Founders Fund, Tiger Global, SoftBank, a16z