Facebook Grows Up

As he describes it, this is a mathematical construct that maps the real-life connections between every human on the planet. Each of us is a node radiating links to the people we know. "We don't own the social graph," he says. "The social graph is this thing that exists in the world, and it always has and it always will. It's really most natural for people to communicate through it, because it's with the people around you, friends and business connections or whatever. What [Facebook] needed to do was construct as accurate of a model as possible of the way the social graph looks in the world. So once Facebook knows who you care about, you can upload a photo album and we can send it to all those people automatically."

Zuckerberg believes that this is what makes Facebook so compelling: as your friends join Facebook, that part of the social graph—the part that matters to you—moves into the digital fast lane and you're getting more out of your connections than you ever could have imagined. (Of course, since your friends on the graph are connected to other people, you have the advantage of seeing their friends, and expanding your circle.) Unlike services like the giant MySpace—which at more than 70 million users still wins in raw numbers—Facebook is not a place where emerging stand-up comics, hip indie bands and soft-porn starlets try to break out by tagging thousands of people as virtual friends. Zuckerberg even says Facebook isn't intended as a venue to seek out new people, though certainly it's possible to locate promising strangers whose relationship status is "anything I can get." (Proof of concept is Aaron Byrd, who as a Texas-born Harvard senior searched through Facebook networks looking for women named Grace—hey, he likes the name—lighting on a pretty U of Georgia sophomore. First he friended her and then, reader, he married her.)

Still, the Facebook experience is built around people you know, and the center of the page is a News Feed where the stories largely consist of the activities, brief status reports, photo and video postings, and comments from those you have earmarked as friends. Facebook also places ads on the News Feed, so after learning that Sue is out of her relationship and Francis has posted a picture, you may get a "sponsored story" featuring the Geico cavemen. News Feed ads are "well targeted—people like the content," Zuckerberg says, unconvincingly. Facebook also takes in revenue, from banner ads sold by Microsoft, in a partnership that's contracted until 2011.

These were stakes undreamed of when Zuckerberg, a computer-savvy Harvard sophomore who grew up in Westchester County, N.Y., started a site called thefacebook.com in February 2004. The name refers to the yearbook-style booklets of photos and vital statistics that incoming freshmen receive at Harvard. (Late the previous year Zuckerberg had apparently agreed to do some of the computer coding for a different planned social-networking site. The founders of that site, ConnectU, are suing Zuckerberg, charging that the then sophomore intentionally stalled, then took the idea from them. Last month a Massachusetts judge indicated that ConnectU's case might be flimsy, asking the plaintiffs to come up with more evidence than "dorm-room chitchat.")

Zuckerberg's site was an instant success. "It was a pretty bare-bones, uploaded Harvard directory when I signed up on the first day—but it became an immediate distraction," says Olivia Ma, user No. 51, who knew Zuckerberg because he lived in her dorm. "Within a few weeks it seemed the whole school signed up." Indeed, two weeks after its release The Harvard Crimson reported the site had already attracted 4,300 students, faculty and alumni.

Zuckerberg had done some things very right. "In the Ivy League, where very few incoming freshmen know more than one or two people, the facebook is a really key piece of the social infrastructure," says Danah Boyd, a researcher at the UC Berkeley School of Information. "Zuckerberg made it interactive. It had a slight social stalking element, too. It was addictive, it was juicy—a great way to see what was going on." Another key feature: only those in the Harvard.edu Internet domain could get in. "The fact that you could only see people on your network was crucial," says Boyd. "It let you be in public, but only in the gaze of eyes you want to be public to."