Between 1am and 4am, over three hours very early that morning, Mark Zuckerberg copied all the .jpg photos from 9 residential Harvard houses, then sets up a "Facemash" web site which brings up two images at a time and allows users to specify the more "attractive" image, left or right.
The Web site goes live Friday night, with its URL www.fashmash.com written on his dormroom window. By Sunday night, with so much traffic hitting that site from Harvard students that Mark is unable to log on, Mark shuts it down. On 18th November, he is censured by Harvard's admin board for his activity.
They had been working with other programmers on it for a year, and they hand over to Mark all their ideas and software code. One idea they had had was adapting it to other University Colleges, and because they were using their own software and web servers and they weren't needing approval from the University administrations, news of it would spread by word of mouth. Mark sent an email back, saying he should be finished with the code inside a week, though he later wrote emails in December and January saying he had been delayed.
Later Mark insisted "he didn't use one line of their software code". Regarding the ideas themselves, he said he, Mark, had "better" ideas.
February 4, 2004 www.thefacebook.com web site goes live. Hundreds of students at Harvard immediately start registering their names and uploading their profiles, classes, relationship status, etc, etc, and photo (just one photo per student) at that time 
- Sean now introduces Mark to Peter Thiel. Peter Thiel had co-founded Paypal in 1999, and after Elon Musk got involved in 2000 Peter sold Paypal to eBay in 2002 at a $55 million profit. Peter was now a wealthy man and a potential angel investor.
- Mark is encouraged by Sean to drop out of college so he can devote his whole time to the project.
- Eduardo, in a somewhat hissy fit at the use of his investment on personal expenses – he was during the summer break working in New York and trying to find advertisers – shuts down the Facebook bank account. Mark has to get an immediate loan from his family to keep the servers online, about $100,000. About now he makes plans to dilute Eduardo's voting share as well as his ownership share, at the time it was 30% plus of the company.
- Peter Thiel makes an angel investment of $500,000, valued at a 7% share of Facebook. The company undergoes a restructure. Eduardo's share is now apparently 24%.
- In July 2004, following the restructure, Sean is appointed president.
Later that same week Sean was at a house party in North Carolina, the house being rented by Sean, and a police raid discovered cocaine to be present. Although Mark apparently put no pressure on Sean to step down, other directors did, and Sean resigned as president.
The book however is published in 2009, followed by the movie "The Social Network" in 2010.
In one review, "Mezrich portrayed both Zuckerberg and Saverin as socially awkward outsiders" as opposed to "Hollywood's girl obsession ... Eisenberg's portrayal of Mark introduced a measure of silken menace to the character that Mezrich’s on-the-page Zuckerberg lacks" Incongruous movie quotes gave Zuckerberg, who could otherwise lapse into long periods of silence, tremendous pleasure. He also inserted them in the site. Whenever you searched for something in those days there was a little box below the results that had tiny type that said, “I don’t even know what a quail looks like.” It’s a throwaway line from The Wedding Crashers. Another quote that appeared there was a Tom Cruise line from Top Gun: “Too close for missiles. Switching to guns.” The quotes came to encapsulate, in the fashion of schoolboy in-jokes, the spirit of the company — playful, combative, and despite the technical sophistication, a bit juvenile. Students at colleges around the U.S. spent hours arguing about the significance of these inscrutable epigrams.
As the Facebook boys started dealing increasingly with real business professionals, a reputation for rambunctiousness spread throughout the valley. “It’s Lord of the Flies over there,” one executive told an executive recruiter. Zuckerberg had to be careful which business card he handed out at meetings. He had two sets. One simply identified him as “CEO.” The other: “I’m CEO…bitch!”
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— Ben Mezrich’s The Accidental Billionaires.
Comment from Eduardo "And I would never throw a laptop at someone, like it appears in the movie. Not even at Mark."
In 2022 Mark owned 366.87 million shares, which included 57.9% of the total voting shares, giving him effective control of the company.
In 2024, Facebook shares have increased on the open market to about $US500.00 each, with 2,566,000,000 shares outstanding.