A series of messages purportedly sent by Mark Zuckerberg to friends at Harvard University in 2004 suggest a steely side to the founder of Facebook.
The messages, published by the Business Insider website ahead of Facebook's hotly-anticipated IPO, show a 19-year-old Zuckerberg openly discussing issues of user privacy, business and hacking.
In one message, Zuckerberg boasted about deactivating student accounts on the internal Harvard social network ConnectU.
"I got bored so I started deactivating accounts on ConnectU haha," he wrote.
Zuckerberg also joked to a friend about having thousands of emails, photos and other information belonging to fellow students on his nascent Harvard social network.
"Yeah, so if you ever need info on anyone at Harvard, just let me know," he said. "I have over 4,000 emails, pictures, addresses, SNS."
Asked how he got the information, Zuckerberg replied: "People just submitted it... I don't know why... They 'trust me'... dumb f**ks."
In one exchange with a friend, Zuckerberg appears to confirm that he secretly hacked into the website of University newspaper The Harvard Crimson by guessing emails and passwords on the college database.
"So I want to read what they said about me before the article came out and after I complained," he said.
"So I'm just like trying the email/passwords of everyone who put that they're in the Crimson. I wonder if the school tracks stuff like that."
It appears from Business Insider's leaked messages that Zuckerberg also discussed how he planned to ditch the Winklevoss twins, fellow students at Harvard with whom he later fought a legal dispute over who had the initial idea for Facebook.
He told a friend: "I'm going to f**k them."
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In another exchange, Zuckerberg talked about Eduardo Saverin, the Brazilian who was Facebook's co-founder and first investor. Zuckerberg said that he wanted to dilute Saverin's shares in the company to control more himself.
Warned that this could result in a lawsuit, he replied: "I won't pay the legal fees. The company that buys us will haha."
However, Zuckerberg also said that Saverin was more intent on making money from Facebook, whereas he was just "content to make something cool".
Facebook has not confirmed or denied that the messages are authentic, but Zuckerberg told The New Yorker in September 2010 that he regretted things that he had written when younger.
"If you're going to go on to build a service that is influential and that a lot of people rely on, then you need to be mature, right? I think I've grown and learned a lot," he told the magazine.
He added: "I think a lot of people will look at that stuff, you know, when I was 19 and say, 'Oh, well, he was like that... He must still be like that, right?'"
Later today (May 18), Zuckerberg will ring the bell on Wall Street marking Facebook's historic flotation on the US stock market, with a public offering that will value the company at $104bn and make the 28-year-old one of the richest people on the planet.