Read Paul Graham’s initial post announcing YC’s first batch

Y Combinator was founded in 2005 to bridge gaps between founders and investors

In one of Paul Graham’s essays on his website, he took the time to explain how and why he and his cofounders (including his girlfriend at the time, and now wife, Jessica Livingston), came up with the idea of and eventually created Y Combinator.

YC was partly inspired by an investor named Julian Weber

Y Combinator Cofounder Paul Graham’s former professor’s husband Julian Weber provided $10K in seed funding to Graham’s previous startup, Viaweb in its early days. In exchange, Weber received 10% of the company. Weber’s involvement inspired Graham to start a program where investors were more involved with the companies they contributed seed funding to.

Y Combinator cofounder Paul Graham keeps a public archive of his insightful essays

In addition to cofounding Y Combinator and other companies before it, Paul Graham is a prolific writer and artist. He chronicled many of his thoughts while building Y Combinator in a series of dozens of candid essays, all of which you can read in an online archive.

Where are the first batch of YC founders now?

Reddit was one of the companies in Y Combinator’s first batch. While OpenAI wasn’t among the companies started at YC, Sam Altman, who would later become the AI company’s CEO, had a different company called Loopt in the first batch.

Y Combinator tends to outperform many other Silicon Valley startup accelerators

In a podcast episode, Garry Tan—CEO of startup accelerator Y Combinator—speaks about how YC has a better track record than the rest of Silicon Valley at placing bets on startups. Learn how Tan earned his first million dollars, as well as lessons from other successful businesspeople, including Y Combinator’s Paul Graham.

Y Combinator changed the way startups around the world are built

Many of the philosophies that the leaders of Y Combinator have infused into the program’s portfolio companies have become the playbook for building the next big thing, such as its focus on founder personality and more.

Stanford’s ‘How to Start a Startup’ series

Stanford’s archive of lectures about creating a startup includes advice from Y Combinator notables such as former YC president and OpenAI CEO Sam Altman and YC Cofounder Paul Graham.

CEO Gary Tan explains Y Combinators guiding philosophy

Hear YC President and CEO Garry Tan talk about why he values earnesty and excellent communication skills in YC founders, his thoughts on AI, and more in this unexpectedly deep and in-depth interview.

The Y Combinator startup directory includes every company YC has funded

The startup accelerator has funded more than 5,000 companies over the years. This YC-specific search engine lets you look up any company to find out if it's a YC alum.

Explore the schedule of a three-month YC batch

During the three months that founders accepted into Y Combinator spend on YC’s California campus, they receive mentorship from YC partners, networking opportunities, and, overall, a ton of time to build and scale their companies.

Yahoo acquired Paul Graham's former startup Viaweb in 1998

Viaweb was the web app tech startup that Paul Graham, Robert Morris, and Trevor Blackwell cofounded before they started Y Combinator. The company sold for $49M and Viaweb was rebranded as the Yahoo Store.

Dive deep into the numbers that shape each YC deal

Y Combinator invests $500K into each company in any given batch. $125K of that investment converts into a fixed 7% in ownership of the startup, and the other $375K is invested on something called an uncapped MFN safe. YC explains what that means and more terms of the deal in a detailed article on their website

'Founder mode' is the idea that startup founders should take a hands-on approach to running their businesses

In 2024, Y Combinator cofounder Paul Graham popularized the idea of "founder mode" when he wrote a viral manifesto in response to a talk that Airbnb CEO Brian Chesky gave about leadership styles. Graham positioned the concept of founder mode as the opposite of manager mode—when founders hire executives and middle managers to run their companies and make decisions that Graham says are better left to founders.

ChatGPT was conceived over dinner at a Silicon Valley hotel

A guest list of tech leaders, including Elon Musk, Peter Thiel, and LinkedIn cofounder Reid Hoffman, met to discuss how to counter Google's efforts to create human-level cognition systems. The group initially committed a reported $1B to launch the effort.

How venture capital firms came to be

The venture capital firm that kickstarted an industry.

Apple's first backer recruited his own CEO to help manage the company

Wanting Steve Jobs and Steve Wozniak to focus on developing Apple computers, Mike Markkula brought in his colleague from Fairchild Semiconductor, Michael Scott. As employee number five, Scott helped professionalize the fledgling computer company and getting manufacturing off the ground. (Some users may experience a paywall.)

The first-ever tweet on X was sent on March 21, 2006, at 9:50 pm

The short, declarative message launched what would eventually become one of the world's most influential social media platforms. As of 2020, about 10% of X users are responsible for 92% of all posts.

Prediction market Polymarket's CEO dropped out of New York University

Polymarket CEO Shayne Coplan started building Polymarket when he was 21. Polymarket has been backed by billionaire investors such as Peter Thiel and Vitalik Buterin.

The early success of Facebook made Mark Zuckerberg a college campus celebrity

Within 24 hours of launching in 2004, more than 1,200 Harvard students signed up to the platform, which quickly expanded to other Ivy League and Boston-area schools within months. By year's end, Zuckerberg left Harvard to run the company in California.

YouTube's first video was grainy video of co-founder Jawed Karim at the zoo

Some 500 hours of content are posted to YouTube every minute. The video at the beginning of that massive growing stream of content is this one—"Me at the Zoo." Uploaded in April 2005 by YouTube co-founder Jawed Karim, it shows him at the San Diego Zoo talking about elephants.

PayPal was started in 1998 by Peter Thiel

By the year 2002, PayPal went public for the first time—but that was far from the end of its business story. eBay later bought PayPal, then eventually spun it off. PayPal IPO’d for a second time in 2015.

WeWork filed its first S-1 in 2019

When WeWork prepared to file for its initial public offering in 2019, its S-1 revealed its poor financial state to the public.

Amazon sold its first book on April 3, 1995

Before selling everything on the internet, Amazon started as an online bookstore. The company's first customer was a man named John Wainright, who purchased "Fluid Concepts And Creative Analogies: Computer Models Of The Fundamental Mechanisms Of Thought" by Douglas Hofstadter. There's a building named after Wainwright on Amazon's Seattle campus.

The name 'Silicon Valley' arose from the founding of Shockley Semiconductor Laboratory in Fairchild Semiconductor in 1956-57, founded near Stanford University in Palo Alto

Read Linus Torvalds' commenting on his first posts about Linux in the comp.os.minix newsgroup

On August 1, 1991, he posted a request on what would be the first version of Linux, writing, "I'm doing a (free) operating system (just a hobby, won't be big and professional like gnu) for 386(486) AT clones. [...] I'd like any feedback on things people like/dislike in minix, as my OS resembles it somewhat."

The story of the debut 1967 Consumer Electronics Show

Read an account of the origins of the first CES in New York in 1967, a story which is surprisingly difficult to find information about.

Venture capital is a form of funding provided to early-stage companies with high growth potential, typically in exchange for an equity (or ownership) stake

Elk Cloner, the first computer virus to spread in public, was written as a practical joke by Richard Skrenta, a Pittsburgh high school student.

Children are now three times more likely to say they want to be a YouTuber when they grow up than an astronaut, with some even attending 'YouTube camps' that teach kids how to create content for the platform.

Warren Buffett's former professor Benjamin Graham is known as the 'father of value investing,' a strategy in which investors seek to buy stocks trading below their intrinsic worth.

How Amazon operates a 'flywheel' business model, a self-reinforcing cycle that drives continuous growth

A Yale student wrote a profound essay about the consulting industry's influence on elite college students that was published in a book of her writing after she died in a post-graduation car accident.

In 2025, four executives from large tech companies were given positions in the US Army Reserves—including Palantir Chief Technology Officer Shyam Sankar, which reinforced Palantir's ties with the US military and its role as a leading defense partner.

Learn how to read a prospectus, the juicy document that any company must file with the SEC before going public.

English mathematician Ada Lovelace wrote the first computer algorithm a century before computers existed and hypothesized that computing devices would one day be able to compose music—foreseeing the generative AI systems of today.

Up to a million Girl Scouts sell about 200 million cookie boxes every spring, generating $800 million, largely because refusing a child is frowned upon

Budweiser stores yeast derived from the original 1800s strain in a secret bunker, which only the Head of Yeast Management can access—not even the CEO

Hear about the 250-year history of the United States Postal Service, complete with some of its strangest deliveries, important innovations, and the figures that made it an American institution.

Search a massive database of over 4 decades of clues from the TV quiz show 'Jeopardy!'

Legendary architect Frank Lloyd Wright designed the SC Johnson headquarters in Wisconsin, aiming to make a cathedral-like workplace

As of 2025, the most cited papers in science include a review of graphene, methods to improve image recognition, streamlining electron density calculations, and optimizing protein studies.

Sears sold DIY house kits starting at $600 in its famous catalog from 1908 through the 1940s, resulting in roughly 10,000 'Sears and Roebuck houses' being built.

After NASA's Voyager 1 captured Earth as a single pixel as it left the solar system in 1990, astronomer Carl Sagan used the image to reflect on humanity's fragility and the responsibility to protect 'the only world we've ever known.'

American dance legend Martha Graham, sometimes called 'the Picasso of dance,' refused to perform at the 1936 Olympics in Berlin and conceived the piece 'Chronicle' in response to the experience.

The Beatles' US label rejected the band's first two singles, 'Please Please Me' and 'From Me to You,' with one executive calling the band 'dead in the water.'

NBA superstar Victor Wembanyama spent the 2025 summer training with monks in central China to enhance his body and mind.

Memecoins are a type of cryptocurrency—a form of digital currency with a wide variety of uses—created around popular 'memes,' or viral internet jokes.

The hormonal disorder PCOS was renamed PMOS in 2026, a move designed to improve care and research by shifting the focus to the hormonal causes of this condition that affects 1 in 8 women.

Long before Major League Baseball began allowing instant replay for balls and strikes, an umpire reluctantly used the technology to determine whether a hit was a home run, a move that inadvertently ushered in a new era for the sport.

'Shogun,' a 1980s TV series, helped popularize sushi in the US by stimulating an American interest in Japanese culture.