Mark Zuckerberg is a genius.

Not in the Asperger’s, autistic way depicted in the very fictional movie The Social Network, the cognitive genius of exceptional ability. That’s a modern definition that reduces the original meaning.

Nor would I say he was the Steve Jobsian product genius, either. Anyone claiming as much will have to explain the crowded graveyard of forgotten Facebook product failures. Remember “Home,” the Facebook-enabled home screen for Android phones, launched with much fanfare at a Facebook press event in 2013, Zuck appearing alongside the C.E.O. of the soon-to-be-disappointed smartphone-maker HTC? Or Facebook’s misguided bet on HTML5 in 2012, which slowed the mobile app to a frustrating crawl? How about Facebook’s first version of Search, available in English only, mostly useful for checking out your friends’ single female friends, and since discontinued? The stand-alone mobile app Paper, which was a shameless rip-off of Flipboard? Some unlaunched products I can’t name consumed massive resources, dying internally after Zuck changed his mind and shut them down.

If he’s a product genius, then there’s lots of serendipity counterbalancing his divine madness.

No. I submit he is an old-school genius, the fiery force of nature possessed by a tutelary spirit of seemingly supernatural provenance that fuels and guides him, intoxicates his circle, and compels his retinue to be great as well. The Jefferson, the Napoléon, the Alexander... the Jim Jones, the L. Ron Hubbard, the Joseph Smith. Keeper of a messianic vision that, though mercurial and stinting on specifics, presents an overwhelming and all-consuming picture of a new and different world. Have a mad vision and you’re a kook. Get a crowd to believe in it as well and you’re a leader. By imprinting this vision on his disciples, Zuckerberg founded the church of a new religion. All the early Facebook employees have their story of the moment when they saw the light and realized that Facebook wasn’t some measly social network like MySpace but a dream of a different human experience. With all the fervor of recent converts, newly recruited followers attracted other committed, smart, and daring engineers and designers, themselves seduced by the echoes of the Zuckian vision in others.

Down in the Valley

Then there was the culture he created.

Many cool Valley companies have engineering-first cultures, but Facebook took it to a different level. The engineers ran the place, and so as long as you shipped code and didn’t break anything (too often), you were golden. The spirit of subversive hackery guided everything. In the early days, a Georgia college kid named Chris Putnam created a virus that made your Facebook profile resemble MySpace, then the social-media incumbent. It went rampant and started deleting user data as well. Instead of siccing the F.B.I. dogs on Putnam, Facebook co-founder Dustin Moskovitz invited him for an interview and offered him a job. He went on to become one of Facebook’s more famous and rage-filled engineers. That was the uniquely piratical attitude: if you could get shit done and quickly, nobody cared much about credentials or traditional legalistic morality. The hacker ethos prevailed above all.

This culture is what kept 23-year-old kids who were making half a million a year, in a city where there was lots of fun on offer if you had the cash, tethered to a corporate campus for 14-hour days. They ate three meals a day there, sometimes slept there, and did nothing but write code, review code, or comment on new features in internal Facebook groups. On the day of the I.P.O.—Facebook’s victory rally—the Ads area was full of busily working engineers at eight P.M. on a Friday. All were at that point worth real money—even fuck-you money for some—and all were writing code on the very day their paper turned to hard cash.

Left, Facebook headquarters; Right, Google’s Mountain View, California, campus. Left, © Aerial Archives/Alamy Stock Photo; Right, Marko Priske/Laif/Redux.

At Facebook, your start date was celebrated by the company the way evangelicals celebrate the day they were baptized and found Jesus, or the way new American citizens celebrate the day they took their oath in front of the flag. This event was called (really) your Faceversary, and every colleague would rush to congratulate you on Facebook (of course), just as normal people did for one another on their birthdays. Often the company or your colleagues would order you a garish surprise bouquet for your desk, with one of those huge Mylar balloons in the shape of a 2 or whatever. When someone left Facebook (usually around when the balloons said 4 or 5), everyone would treat it as a death, as if you were leaving the current plane of existence and going to another one (though it wasn’t assumed this next plane would be better than the current one). The tombstone of your Facebook death was a photo posted on Facebook of your weathered and worn corporate ID. It was customary to include a weepy suicide note/self-written epitaph, and the post would garner hundreds of likes and comments inside a minute.