In November 2003, at the suggestion of Victor Gao, the Winklevosses and Narendra approached Mark Zuckerberg about joining the HarvardConnection team. The previous HarvardConnection programmers had reportedly made progress on coding front-end pages, the registration system, a database, back-end coding, and a way users could connect with each other, which Gao called a "handshake". In early November, Narendra emailed Zuckerberg saying, "We're very deep into developing a site which we would like you to be a part of and ... which we know will make some waves on campus." Within days, Zuckerberg was talking to the HarvardConnection team and preparing to take over programming duties from Gao. On the evening of November 25, 2003, the Winklevosses and Narendra met with Zuckerberg in the dining hall of Harvard's Kirkland House, where they explained to Zuckerberg the HarvardConnection website, the plan to expand to other schools after launch, the confidential nature of the project, and the importance of getting there first. During the meeting, Zuckerberg allegedly entered into an oral contract with Narendra and the Winklevosses and became a partner in HarvardConnection. He was given the private server location and password for the unfinished HarvardConnection website and code, with the understanding that he would finish the programming necessary for launch. Zuckerberg allegedly chose to be compensated through an interest in the enterprise (sweat equity).
On November 30, 2003, Zuckerberg told Cameron Winklevoss in an email that he did not expect completion of the project to be difficult. Zuckerberg writes: "I read over all the stuff you sent and it seems like it shouldn't take too long to implement, so we can talk about that after I get all the basic functionality up tomorrow night." The next day, on December 1, 2003, Zuckerberg sent another email to the HarvardConnection team. "I put together one of the two registration pages so I have everything working on my system now. I'll keep you posted as I patch stuff up and it starts to become completely functional." On December 4, 2003, Zuckerberg writes: "Sorry I was unreachable tonight. I just got about three of your missed calls. I was working on a problem set." On December 10, 2003: "The week has been pretty busy thus far, so I haven't gotten a chance to do much work on the site or even think about it really, so I think it's probably best to postpone meeting until we have more to discuss. I'm also really busy tomorrow so I don't think I'd be able to meet then anyway." A week later: "Sorry I have not been reachable for the past few days. I've basically been in the lab the whole time working on a cs problem set which I'm still not finished with." On December 17, 2003, Zuckerberg met with the Winklevosses and Narendra in his dorm room, allegedly confirming his interest and assuring them that the site was almost complete. On the whiteboard in his room, Zuckerberg allegedly had scrawled multiple lines of code under the heading "Harvard Connection," however, this would be the only time they saw any of his work. On January 8, 2004, Zuckerberg emailed to say he was "completely swamped with work [that] week" but had "made some of the changes ... and they seem[ed] to be working great" on his computer. He said he could discuss the site starting the following Tuesday, on January 13, 2004. On January 11, 2004, Zuckerberg registered the domain name thefacebook.com. On January 12, 2004, Zuckerberg e-mailed Eduardo Saverin, saying that the Facebook site [thefacebook.com] was almost complete and that they should discuss marketing strategies. Two days later, on January 14, 2004, Zuckerberg met again with the HarvardConnection team; however, he allegedly failed to disclose registering the domain name thefacebook.com or developing a competing social networking website. Rather, he allegedly reported progress on HarvardConnection, told the team he would continue to work on it, and would email the group later in the week. On February 4, 2004, Zuckerberg launched thefacebook.com, a social network for Harvard students, designed to expand to other schools around the country.