After Yu left abruptly, CEO Mark Zuckerberg trotted out the tired time-with-family cliché to explain his departure. But in the case of Facebook VP Chamath Palihapitiya, the cliché seems to be literally true, and the departure temporary. Sort of. Palihapitiya, a former AOL executive who now heads Facebook's growth initiatives, has said he plans to leave the company altogether, but was persuaded to take a four-month paternity leave instead.

A less likely rumor we've heard: That COO Sheryl Sandberg has been issuing ultimatums, that either she goes or Zuckerberg. That doesn't square with Sandberg's style. She's an experienced Washington operative and former Google executive who always works behind the scenes to get what she wants. But she does have ties to Facebook investors, including venture-capital firm Accel Partners and Elevation Partners' Marc Bodnick, who happens to be her brother-in-law. Could she quietly be spreading the word that it's time for Zuckerberg to go? And if Zuckerberg gets wind of her efforts, could her time be up?

There's an innocent explanation: His digital-music startup, Project Playlist, which recently scored a deal with EMI, has its offices in a downtown Palo Alto building shared with Facebook. But that doesn't explain why our tipster, who spotted Van Natta twice today, saw him walking from that building to another Facebook office. Could be a coincidence. Or it could be that Van Natta, who remains close to Facebook executives like Chamath Palihapitiya and Dan Rose, is up to something.

Zuckerberg tends to fall in love with his latest hire, and give that person more and more responsibility, until there's some obvious failure. Even from the outside, it's crystal clear that's what happened with Oven Van Natta, Sandberg's predecessor as COO; it happened, too, with Chamath Palihapitiya, whose portfolio waxed and waned with Zuckerberg's favor.

So Sandberg's rampage through Facebook's technical ranks is just par for the course. If past experience is any indication, Zuckerberg's hanging back, keeping his fingerprints off her actions, and waiting for her to trip up. Her botched handling of ace product marketer Ben Ling's departure may be what turns Zuckerberg against Sandberg — or not. What's clear: When his disfavor arrives, it will be sharp, cold, and unmovable. Sandberg won't know what hit her. And Zuckerberg will be all smiles — like he was today in San Francisco.

That Facebook would throw this all in Schrage's lap is telling — about both Facebook and Schrage. Schrage, having shrunk his role considerably by following Sandberg from Google to Facebook, is likely desperate for some scrap of increased authority. And Facebook's geeks, getting assailed in the press for their decisions, are eager for someone slicker than they are to take the abuse.

Still, it needs to be said: Facebook's platform is technically immature, and needs a technical manager. Chamath Palihapitiya, whom Schrage is replacing as its head, may be inept at public relations — look at last year's debacle with Facebook's privacy-invading Beacon feature. But that doesn't mean he's bad at running a computing platform.

Schrage may not be a geek, but he'll now need to play the part. This should be fun to watch. And he can take comfort in one precedent: This isn't the first time the owner of an important computing platform has, in desperation, put a gladhanding slickster in charge. Microsoft's Kevin Johnson, who now oversees Windows, previously ran its sales operations. He also negotiated Microsoft's Facebook investment. He would surely approve.

"A handful of large companies have expressed interest in seeing how it would work because organically at least 50 percent of their employees are already on Facebook," he said. The staid enterprise execs in the room promptly began shrieking. "Ads in the enterprise are extremely unfeasible," said a self-interested David Thompson, CEO of ad-free enterprise softwaremaker Genius.com. "No one wants it, certainly not corporate IT," he said. "I say it's doomed."

Previously:

• A is for Adelson, who cofounded Digg


• B is for Botha, who sold YouTube big


• F is for Fitzpatrick, and "hookers and blow"


• L is for Levchin, who never goes slow

The protests over Beacon, a program which reports users' activities on other websites to their friends on Facebook, have been compared to last year's fuss over news feed. In fact, there's no comparison: Actual complaints from users about Beacon have been far, far fewer. The introduction of a news feed was a radical change to Facebook's behavior. Beacon, which merely extends Facebook's reporting of activity on its site to others, does not change users' experience of the site in a dramatic way.

Facebook has been its own worst enemy — doing far more damage than any underemployed blogger could. The company made just about every conceivable mistake in the marketing of Beacon — from overhyping it to Madison Avenue, misleading advertisers about how optional it was for users, and failing to consider the consequences of reporting users' purchases to friends and family over the holiday shopping season.

Someone should take the fall for this. Facebook executive Chamath Palihapitiya, in charge of marketing, has likened the introduction of Beacon to an experiment. "We want people to try it, to see it in action," he told the New York Times. "Our point of view is, let's give people the ability to sample it."

A sensible laboratory trial. But let's run a different experiment. Why did Beacon draw such a critical reaction from the press, while the news feed, a year ago, a much larger user revolt, make less of a splash? We can control for several variables.

Mark Zuckerberg, then as now, was CEO. PR head Brandee Barker, excoriated by Quittner and blogger Robert Scoble for the company's media relations, joined Facebook shortly before the news feed fuss. (It turns out that Scoble, who accused Barker of being unresponsive, never even even bothered to ask for an interview.) Owen Van Natta, then COO, now the company's chief revenue officer, was equally involved in both incidents, from what we hear.

The new variable in the Beacon trial is Palihapitiya himself, who joined the company just a few months ago after a long career at AOL. He's clearly a talented executive, trained in the new school of marketing through scientific thinking and quantitative analysis. Try something, and if it fails, discard it and move on. Perhaps that's what Zuckerberg should do with Palihapitiya.

Chamath Palihapitiya, the former AOL executive, now heads up marketing; having criticized Silicon Valley's white-male old boys' club, Palihapitiya must surely be pleased with Van Natta's comeuppance. Matt Cohler, the early LinkedIn employee cofounderwho jumped to Facebook some time ago, is now in charge of "business operations" and strategy. Gideon Yu, the recently hired CFO, is now free to fib about Facebook's finances, as he did as YouTube's CFO after that company was acquired by Google. And close Zuckerberg associates Dustin Moskovitz and Adam D'Angelo now have tighter reins on the company's products and technology.

But Zuckerberg could be setting himself up for a fall. By elevating Van Natta's rivals, he's going to find himself spending time on personality conflicts, infighting, and turf warfare instead of tending to the needs of his beloved users. Palihapitiya, Cohler, and Van Natta, for example, are, by their titles, charged with Facebook's "operations." The more Zuckerberg's executives spar over fields of authority, the less attention they'll pay to business. Zuckerberg has asserted his power — at the cost, potentially, of his abiity to get things done.

Here's how the San Francisco Chronicle summarized his comments — and how Mayfield spun them after the fact:

But Mayfield Fund venture capitalist Chamath Palihapitiya said that despite his success in Silicon Valley, he still sees a white male circle of insiders that he can't penetrate, with exclusive dinner parties and country clubs that he isn't part of.

Whatever. Palihapitiya's departure from the world of venture capital, not five months after the brouhaha erupted, by itself suggests that all is not meritocratic at Mayfield. But if he thinks he's leaving a world of privilege for a league of scrappy strivers, he's sorely mistaken. At Facebook, after all, he's going to be working for Mark Zuckerberg, a graduate of Phillips Exeter Academy and Harvard College who grew up in Westchester County.