In "Facebook: The Inside Story," author Steven Levy offers an unprecedented look into how Mark Zuckerberg built Facebook into the world's largest social network.

Levy, a writer at Wired magazine, says Zuckerberg "vowed to make privacy a core component" of Facebook from its early days, but noted he often fell short of that aim.

However, the book leaves out a series of messages sent by Zuckerberg, first reported by Business Insider in 2010, where he calls people "dumb f--ks" for trusting him with their information.

The exchange offers crucial additional insight into Zuckerberg's early thoughts on privacy, as Facebook continues to draw criticism for how it handles users' data.

Levy told Business Insider that he included examples of Zuckerberg's actions that were "more illustrative" than words, like when he accessed users' accounts to hack their emails.

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One of the most salient topics surrounding Facebook is privacy. It has been at the center of many of the company's biggest scandals, from Cambridge Analytica to breaking Apple's App Store rules so it could pay people to spy on them, with Facebook's privacy missteps ultimately netting it a $5 billion fine from the Federal Trade Commission.

In his new book about the rise of the internet giant, " Facebook: The Inside Story ," Wired editor and writer Steven Levy offers insightful details about CEO and cofounder Mark Zuckerberg's approach to privacy, especially in Facebook's early days. But the book leaves out one particularly noteworthy instant message exchange that suggests Zuckerberg's privacy views weren't exactly straightforward.

In 2003, while Zuckerberg was still at Harvard and experimenting with online social networks, he spun a prank website called "Facemash" that showed pictures of classmates and asked students to vote on who was most attractive.

The catch? Zuckerberg had hacked into the university's computer system to download the photos, without consent from any students.

Administrators quickly cut off Zuckerberg's internet access and threatened to expel him, the school's newspaper, The Harvard Crimson wrote at the time. In the immediate aftermath, the Crimson also penned an editorial grilling Zuckerberg for his lack of concern for students' privacy.

"Zuckerberg took the editorial to heart, and vowed to make privacy a core component" of the social media network he was quietly working on, Levy wrote.However, just a year later, Zuckerberg hacked the emails of student journalists at the Crimson by accessing their Facebook login information, a story first reported by Business Insider.

Shortly after launching "The Facebook" from his dorm room, Zuckerberg sent the following messages to a friend, originally reported by Business Insider in 2010:

Zuckerberg: Yeah so if you ever need info about anyone at Harvard Zuckerberg: Just ask. Zuckerberg: I have over 4,000 emails, pictures, addresses, SNS [Redacted Friend's Name]: What? How'd you manage that one? Zuckerberg: People just submitted it. Zuckerberg: I don't know why. Zuckerberg: They "trust me" Zuckerberg: Dumb fucks.

While the exchange suggests Zuckerberg's attitudes toward privacy were somewhat flippant even in the network's early days, the book's author Levy doesn't draw the same parallel.

"If you're talking about Facebook in 2020, there's limited value to holding up an email from when he was 19," Levy told Business Insider by phone, explaining his decision to leave the incident out of the book. Levy said examples like the Crimson email hacking were "more illustrative" of Zuckerberg's approach to privacy.

Zuckerberg told Levy that he regretted the messages and chalked them up to immaturity. But he also expressed frustration, in a text to Levy, that "'old instant messages and emails from from when I was a kid kept getting surfaced out of context.'"

Zuckerberg and Facebook did not immediately respond to a request for comment.