Justin Timberlake was the only actor who met his real-life character (Sean Parker) before the founding of Facebook and this film. Armie Hammer and Josh Pence met their real-life characters, the Winklevoss twins after filming. The twins enjoyed Hammer and Pence's performance so much they attended a couple screenings of the film.
Because director David Fincher was unable to find any suitable identical twin actors to play real-life identical twins Cameron Winklevoss and Tyler Winklevoss, two unrelated actors were hired to play each brother - Armie Hammer as Cameron and Josh Pence as Tyler. Fincher thought that Hammer looked the most like the real brothers, so for some scenes, the visual effects team photographed Hammer speaking Tyler's lines and created a computer-generated model of his face to paste over Pence's. Traditional split-screen work, with Hammer's separate performances as each brother stitched together in the same frame, was also used.
The original banner at the top of Facebook.com included a stylized portrait of a young Al Pacino. It was designed by Andrew McCollum, a friend of Mark Zuckerberg. The banner used on the website in the film uses a portrait of actor Jesse Eisenberg (who plays Zuckerberg).
During one of the depositions, it is mentioned that the invention of Facebook made Mark Zuckerberg "the biggest thing on a campus that included nineteen Nobel Laureates, fifteen Pulitzer Prize winners, two future Olympians, and a movie star." One of the lawyers then asks, "Who was the movie star?" and the response is, "Does it matter?" This movie star was, in fact, Natalie Portman, who was enrolled at Harvard from 1999 to 2003 and helped screenwriter Aaron Sorkin by providing him insider information about goings-on at Harvard at the time Facebook first appeared there.
During the climactic confrontation between Mark Zuckerberg (Jesse Eisenberg) and Eduardo Saverin (Andrew Garfield), Zuckerberg can be seen wearing an Arm & Hammer t-shirt. Armie Hammer, who plays the Winklevoss twins, is named after his great grandfather Armand Hammer, who is speculated to be named after the company.
The Winklevoss twins were both played by actor Armie Hammer. However, Ralph Lauren model Josh Pence played one of them strictly from the neck down. His face was digitally replaced with Hammer's to make them appear identical, as the two men are unrelated and look nothing alike. The two spent 10 months in twin boot camp to match one another's subtle movements and rapport.
At one point, Mark Zuckerberg refers to the Winklevoss brothers as the "Winklevii", facetiously using the Latin plural for nouns ending in 's'. In fact, Zuckerberg is quite the Latin scholar, having excelled in the classics while attending the Phillips Exeter Academy and taking advanced courses in subjects such as Greek and Latin while at Harvard.
Facebook CEO Mark Zuckerberg was not involved with this film adaptation of author Ben Mezrich's biographical novel 'The Accidental Billionaires', neither did he meet Jesse Eisenberg prior to, or during, the movie shoot.
In October 2010, the real Sean Parker told Vanity Fair that he actually once met Justin Timberlake and that Timberlake wanted to get to know him better for his preparation for his role in this movie. Parker then replied getting to know the real Sean Parker wouldn't help Timberlake at all, because the Parker from Aaron Sorkin's script has little to do with the real person.
The sequence where Mark Zuckerberg leaves a classroom and meets the Winklevoss twins in the hallway was filmed at the University of Southern California in Los Angeles. The classroom he exits is in a different building (Taper Hall of Humanities) from the hallway in which he meets the twins (Grace Ford Salvatori Hall).
Mark Zuckerberg originally planned never to see the movie. He ended up taking several of his employees to see it. He later remarked that, despite some of the film's inaccuracies, they got his clothing right.
Main video editing was done with Final Cut Pro, with extensive work on tweaking, conforming and fixing up shots done with Adobe software, namely After Effects and Premiere. In 2011, the film became the first Academy Award-winner for Best Editing that utilized Final Cut Pro.
On the DVD commentary, Armie Hammer and Josh Pence recount meeting the real Divya Narendra and taking him to meet Max Minghella, who plays him in the film. As a practical joke, Hammer and Pence told Narendra to talk in an Indian accent, as Minghella had been worried about his portrayal and wanted it to be as accurate as possible. Narendra played along, much to the horror of Minghella. Hammer recalls, "Max just turns white and he just starts going, 'I'm so sorry! I'm so sorry! I'm so sorry!' And profusely apologized to him, for, like, thirty minutes."
As part of his research, Jesse Eisenberg read a copy of Mark Zuckerberg's college application. Zuckerberg's essay focused on his love of fencing, so Eisenberg took a couple of lessons. He quickly realized it affected his posture and the way he moved, and applied that knowledge to his portrayal of the character.
Natalie Portman revealed during "Newsweek's 2011 Oscar Roundtable" that she gave a dinner party for writer Aaron Sorkin, while he was writing the script for this movie, to which she invited a bunch of her friends from Harvard. She wanted to give him the chance to listen to first-hand stories about the social life at Harvard University.
Before filming, Jesse Eisenberg created a false Facebook account for research. Eisenberg opened his account under the name of Peter Sagal, the host of the radio show Wait, Wait... Don't Tell Me!, which Eisenberg was listening to at the time. He closed the account when filming wrapped.
According to David Fincher, Harvard weren't very helpful to the crew when they wanted to get as realistic a portrayal as possible of campus life. They refused filming there ever since significant physical damage to the campus during the shooting of Love Story. Philips and Milton Academy had to fill in for it instead.
The only scene Jesse Eisenberg had a problem with was the scene where Mark Zuckerberg films his friends jumping into a swimming pool from a rooftop. Originally Zuckerberg, instead of just filming it, was supposed to join in as well. Eisenberg couldn't imagine Zuckerberg having that kind of fun. By the time it came to film the scene he was relieved the script had been changed so he just observes it instead.
Aaron Sorkin directed the last shot in the film. David Fincher announced he was leaving- Sorkin thought it was a joke until the production crew came up to him asking how to film it. It only amounted to a second's worth of footage anyway, but Sorkin got to announce the final wrap at the end.
The real Lawrence H. Summers called the film's portrayal of his meeting with the Winkelvoss twins "fairly accurate". He went on to say "I've heard it said that I can be arrogant. If that's true, I surely was on that occasion. One of the things you learn as a college president is that if an undergraduate is wearing a tie and jacket on Thursday afternoon at three o'clock, there are two possibilities. One is that they're looking for a job and have an interview; the other is that they are an asshole. This was the latter case. Rarely, have I encountered such swagger, and I tried to respond in kind."
Andrew Garfield was originally asked to audition for Mark Zuckerberg but David Fincher decided he was too good at wearing his heart on his sleeve to play such an emotionally guarded character. Garfield found it helpful to go from reading for Mark to reading for Eduardo, because he felt that Eduardo tried to understand Mark through Mark's point of view.
Andrew Garfield came into rehearsal with a copy of Economics for Dummies. Inspired by that move, Jesse Eisenberg bought C++ for Dummies. According to Eisenberg, both he and Garfield read the introductions of their books and then put them down.
There is actually a Facebook page for "Erica Albright," a character in the film. The profile pictures are of the actress Rooney Mara who plays Albright. It is also listed that she attended Boston University.
At the time of release, there were about 750 million active users on Facebook. If everyone who had a Facebook account at the time went to go see the movie during its theatrical release, it would have grossed somewhere around US $6 billion.
When Facebook hits one million members, the number 1,000,046 appears on the screen after Sean Parker requests a refresh. The producers purposely chose the number to correspond with the running time of the movie at 1:46:46.
Jesse Eisenberg, who is diagnosed with Attention deficit hyperactivity disorder, said in an interview that one of the hardest things about the role was having to deliberately speak and behave in a manner he had struggled against in his own personality his entire life.
Despite the fact that director David Fincher has been a big proponent of digital filmmaking since his 2007 film Zodiac, this is his first film to have been completely shot digitally (both Zodiac and The Curious Case of Benjamin Button had certain shots/segments shot on film).
After Mark Zuckerberg finishes the coding marathon in his dorm room, he then closes his eyes and slowly moves his head back and forth, and Eduardo asks him, "Mark, are you praying?" On the DVD commentary, Aaron Sorkin explained that what Mark was doing was davening, a word that comes from Yiddish and which generally refers to prayer in Judaism, but which also specifically refers to the type of head and body movements that Jews traditionally make while praying. Sorkin mentioned on the commentary that he considered writing Eduardo's line as "Mark, are you davening?" instead of "Mark, are you praying?" to make it clearer to the audience what Mark was doing.
Some behind-the-scenes footage presented as a DVD extra reveals that during the filming of the "facemash montage" (which shows various groups of Harvard students perusing facemash and rating Harvard women against each other for relative attractiveness), one of the actors was instructed to say, "of course she's hot; she's Natalie Portman" while comparing two female Harvard students. That dialogue didn't make it into the finished film, but another oblique reference to Portman's presence on campus did (she is the movie star referred to during the deposition).
Aaron Sorkin and David Fincher wanted to do the movie based solely on a 14-page book proposal that somehow got leaked to Gawker.com right about the time 21 came out; the book hadn't even been written yet, and Ben Mezrich wound up writing it in a hotel room with Sorkin right next to him, handing Sorkin the chapters as they were finished.