In October 2003, Harvard University student Mark Zuckerberg has the idea to create a website to rate the attractiveness of female Harvard undergraduates after his girlfriend Erica Albright breaks up with him. Over the course of a single night, Mark hacks into the databases of various residence halls, downloads pictures and names of female students and, using an algorithm for ranking chess players supplied by his best friend Eduardo Saverin (essentially the Elo rating system, written on a window pane recalling a scene of A beautiful mind), he creates in a few hours a website called “FaceMash. com”, where male students can interactively choose which of two girls presented at a time is more attractive.
Mark is punished with six months of academic probation after the traffic to the site brings down parts of Harvard’s computer network, and he becomes vilified among most of Harvard’s female community. However, the popularity of “FaceMash” and the fact that he created it in one night, while drunk, brings him to the attention of Cameron Winklevoss and Tyler Winklevoss, identical twins and members of Harvard’s rowing team, and their business partner Divya Narendra.
As a result, he gains a job working for the Winklevoss twins as the programmer of their website, Harvard Connection. Soon afterwards, Mark approaches his friend Eduardo and tells him of his idea for what he calls “Thefacebook”, an online social networking website exclusive to Harvard University students. He explains this would let people share personal and social information securely. Eduardo agrees to help Mark, providing a fee of $1,000 to help start the site. Once complete, they distribute the link to Eduardo’s connections at the Phoenix S-K final club, and it quickly becomes popular throughout the student body.
When they learn of Thefacebook, the Winklevoss twins and Narendar believe that Zuckerberg stole their idea while simultaneously stalling on their website. Cameron and Divya want to sue Mark for intellectual property theft, but Tyler convinces them they can settle the matter as “Harvard gentlemen” without resorting to the courts. A few months later, at a lecture by Bill Gates, fellow Harvard University student Christy Lee introduces herself and her friend Alice to Eduardo and Mark. She asks that the boys “Facebook us”, which impresses both of them. The girls invite them to a bar, where they have sex in the toilet.
Mark later runs into his ex-girlfriend, Erica, who is not aware of The Facebook’s existence because she is not a Harvard University student. Stung by this, Mark decides to expand the site to more schools. Christy, Mark, and Eduardo later return to Mark’s room where they outline the structure of the company and their plan for moving forward. By the spring of 2004, the Facebook grows in popularity, and it expands to other schools in the Northeastern United States, while the Winklevoss twins and Narendra become angrier at seeing “their idea” advance without them.
Tyler refuses to sue them, instead accusing Mark of violating the Harvard student Code of Conduct. Through their father’s connections they arrange a meeting with Harvard President Larry Summers, who is dismissive and sees no potential value in either a disciplinary action or in a lawsuit against Thefacebook website itself. Through Christy Lee, now Eduardo’s girlfriend, Eduardo and Mark arrange a meeting with Napster co-founder Sean Parker. When Christy, Mark and Eduardo meet Parker at a trendy Fusion restaruant in New York City, Eduardo becomes skeptical of the eccentric Parker, noting his problematic personal and professional history.
Mark, however, is impressed with Parker since he presented a similar vision of Facebook. Although no deals are reached, Parker suggests that they drop “The” from Thefacebook to make it simply “Facebook”. That summer, Mark moves the company’s base of operation to Palo Alto, California at Parker’s suggestion, while Eduardo remains in New York for seeking advertising support. When Eduardo visits from New York, he is angered to find that Parker is living at the house and making business decisions for Facebook.
After an argument with Mark, the vindictive Eduardo freezes the company’s bank account and returns to New York. Upon returning, Christy and Eduardo argue about his Facebook profile, which still lists him as “single”. Christy accuses Eduardo of cheating on her and sets fire to a scarf he gave to her as a gift. While Eduardo extinguishes the fire, Mark angrily calls him on the phone about freezing the Facebook bank accounts, and reveals that they have secured money from “an angel investor” through Parker’s contacts. As a result of Christy’s jealousy, Eduardo ends his relationship with her.
Meanwhile in England, while competing in the Henley Royal Regatta, the Winklevoss twins become outraged that Facebook has expanded to a number of universities there and they finally decide to sue Mark. Eduardo has also discovered the deal he signed with Parker’s investors allows them to dilute his share of the company from a third to less than one tenth of one percent, while maintaining the ownership percentage of all other parties. He confronts his erstwhile friend Mark at his new Facebook office in downtown L. A. and announces his intention to sue him.
Later that night, Parker, along with a number of Facebook interns, is arrested for possession of cocaine during a party thrown on the occasion of Facebook’s 1 millionth member. It is strongly implied (but never fully explained) that Mark had anonymously tipped off the police to raid the frat house where the party was held and probably had someone plant drugs at the party to intentionally have Parker and his interns arrested to remove them from the Facebook company. The framing device throughout the film shows Mark testifying in depositions in two lawsuits: one filed by the Winklevoss twins, and the other filed by Eduardo.
In the final scene, a junior lawyer for the defense informs Mark they will be settling with Eduardo, since the sordid details of Facebook’s founding and Mark’s cynical personality will make a jury highly unsympathetic to him. The film ends with Mark sending a friend request to his former girlfriend Erica on Facebook, and refreshing the page every few seconds waiting for a response that never comes. In 2003, Harvard University student Mark Zuckerberg (Jesse Eisenberg) is dumped by his girlfriend Erica Albright (Rooney Mara) at a bar.
He returns o his dorm drunk and writes a blog entry about her. This inspires him to create an on-campus website called Facemash which allows users to rate the attractiveness of female students using photographs pilfered from various university systems. Mark receives six months of academic probation after traffic to the site crashes parts of Harvard’s network. Facemash’s popularity and the fact that Mark created it in one night while drunk brings him to the attention of Cameron and Tyler Winklevoss (both portrayed by Armie Hammer) and their business partner Divya Narendra (Max Minghella).
The Winklevoss twins invite Mark to their final club, where Mark accepts a job as programmer for a proposed dating website they call Harvard Connection which will be exclusive to Harvard alumni. Mark approaches his friend Eduardo Saverin (Andrew Garfield) and tells him of his idea for what he calls “Thefacebook”, an online social networking website exclusive to Harvard University students. He explains that this would mimic the popularity of FaceMash but since signing up would be consensual it would avoid the ethical problems of the earlier site.
Eduardo agrees to help Mark, providing $1,000 to help start the site. They distribute the link to Eduardo’s connections at the Phoenix S-K final club, and it becomes popular throughout the student body. When they learn of Thefacebook, the Winklevoss twins and Narendra believe Zuckerberg has stolen their idea while stalling on their website. Tyler and Divya want to sue Mark for intellectual property theft, but Cameron convinces them to settle the matter as “Gentlemen of Harvard”.
During a visiting lecture by Bill Gates (Steve Sires), fellow Harvard University student Christy Lee (Brenda Song) introduces herself and her friend Alice (Malese Jow) to Eduardo and Mark and asks the boys to “Facebook me”. Christy’s use of this phrase impresses both of them. Christy invites them to a bar, where Mark runs into Erica, who is not aware of Thefacebook because she is not a Harvard student. Mark decides to expand the site to Yale University, Columbia University and Stanford University as Thefacebook grows in popularity, while the Winklevoss twins and Narendra watch “their idea” advance without them.
Cameron refuses to sue them, instead accusing Mark of violating the Harvard student Code of Conduct. Through their father Howard’s (John Hayden) connections, they meet with Harvard President Larry Summers (Douglas Urbanski), who is dismissive towards the twins and sees no potential value in either a disciplinary action or in Thefacebook website itself. Through Christy, now Eduardo’s girlfriend, Eduardo and Mark arrange a meeting with Napster co-founder Sean Parker (Justin Timberlake). Eduardo becomes skeptical, noting Sean’s problematic personal and professional history.
Sean presents a vision for Facebook very similar to that of Mark, which earns Mark’s instant admiration. In a parting comment, Sean suggests they drop the “The” from Thefacebook, saying it looks cleaner without the ‘The’. At Sean’s suggestion, Mark moves the company to Palo Alto while Eduardo remains in New York seeking advertising support. Sean advises Mark to keep hold of his ownership of Facebook to ensure that Mark does not lose control of a potentially lucrative business venture.
After Sean promises to expand Facebook to two continents, Mark invites Sean to live at the house he is using as the company headquarters. While competing in the Henley Royal Regatta for Harvard, the Winkle boss twins discover Facebook has expanded to a number of English universities and footage of their lost rowing race final against the Hollandia Roeiclub is posted on it. Cameron relents and they decide to sue. When Eduardo visits from New York, he is angered to find Sean living in their house and making business decisions for Facebook.
Eduardo argues with Mark, with Mark making a demeaning remark regarding Eduardo’s failed attempts to find advertisers. Eduardo freezes the company’s bank account out of anger and returns to New York. Eduardo has been dismayed to learn that his girlfriend Christy is “psychotic,” as he terms it. Upon his return to New York, Christy angrily confronts Eduardo about his Facebook profile, which lists him as “single”. She refuses to believe Eduardo when he reluctantly explains that he does not know how to change his profile. She accuses him of cheating on her and sets fire to a scarf he gave to her.
While Eduardo extinguishes the fire she caused, Mark reveals on the phone that although he was upset that Eduardo almost jeopardized Facebook by freezing the bank account, they have secured $500,000 from angel investor Peter Thiel (Wallace Langham). Eduardo breaks up with Christy and returns to California. While visiting the new headquarters for a meeting, Eduardo discovers the deal he signed with Sean’s investors has allowed them to dilute his share of the company from 34 percent to 0. 03 percent, while maintaining the ownership percentage of all other parties.
He confronts Mark and announces his intention to sue him. During a party celebrating Facebook’s one millionth member, Sean and a number of underage Facebook interns are arrested for possession of cocaine. Sean tries deceiving Mark into believing that he had nothing to do with the incident and that Eduardo stashed the cocaine, but Mark does not believe him and tells him to “go home”. The story is intercut with scenes from depositions taken in lawsuits against Mark and Facebook—one filed by the Winklevoss twins, the other by Eduardo.
The Winklevoss twins claim that Zuckerberg stole their idea, while Saverin claims his shares of Facebook were unfairly diluted when the company was incorporated. At the end, Marylin Delpy (Rashida Jones), a junior lawyer for the defense, informs Mark they will be settling with Eduardo, since the sordid details of Facebook’s founding and Mark’s callous attitude will make a jury highly unsympathetic. After everyone leaves, Mark sends a friend request to Erica Albright on Facebook, and refreshes the page every few seconds waiting for a response.
An epilogue reveals the following information: Cameron and Tyler Winklevoss received a settlement of $65 million, signed a non-disclosure agreement, and rowed in the 2008 Beijing Olympics, placing sixth; Eduardo Saverin received a settlement of an unknown amount and his name was restored to the Facebook masthead as a Co-founder of Facebook; the website has over 500 million members in 207 countries and is valued at 25 billion dollars; and Mark Zuckerberg is the world’s youngest billionaire.