'We're going to go public eventually, because that's the contract that we have with our investors and our employees,' Mr. Zuckerberg said during a recent interview. But, he added, 'we are definitely in no rush.'

Despite hopes in the investment community that Facebook could herald a revival in the Silicon Valley IPO market, Mr. Zuckerberg has made it clear that he won't be dictated to.

At the same time, his delayed-gratification approach offers some insights into what a publicly traded Facebook might eventually look like. It also highlights some of the challenges Mr. Zuckerberg is apt to face in balancing public ownership with his zeal for tight creative and financial control.

Zuck, as he's known to most, lives in a modest house in Palo Alto and often walks to the office. Employees say he's a demanding boss-one who loves to engage in debate but isn't big on lavishing individual praise. According to one engineer, who wrote an internal memo called 'Working with Zuck,' it is unwise to 'expect acknowledgment for your role in moving the discussion forward; getting the product right should be its own reward.'

To the young CEO, Facebook, with its 400-million-plus users, is more than just another tech cog in the cultural landscape. The company's promise, he believes, has to do with facilitating people's ability to share almost any and everything with anyone, at any time-via Web sites, mobile phones, even videogames.

In an era of obsessive communication, 'this push towards things becoming more open is probably the most powerful and transformative social change' barring an event such as war, he says. 'We may be the company that really leads this movement....It's not clear that anyone else is going to manage it correctly.'

Mr. Zuckerberg fits into a long queue of tech barons with grand ambitions. Apple Inc. Chief Executive Steve Jobs in the early 1980s proclaimed that the Macintosh would revolutionize computing. Google Inc.'s founders boasted that its search engine would 'organize all the world's information.'

But unlike some of his predecessors, Mr. Zuckerberg doesn't need huge cash reserves to build factories, a global distribution system or even a massive marketing machine. 'If you don't need that capital, then all the pressures are different, and the motivations [to go public] are not there in the same way,' Mr. Zuckerberg says.

The mission has modulated over time. At Harvard, where Mr. Zuckerberg founded the company from a dorm room in 2004 before dropping out, he saw Facebook as a way for Ivy League buddies to socialize. Photo and message swapping-along with the ability to connect with others by 'friending' them-was just the beginning.

Today, Facebook is busy working on a tool to let users share information about their physical whereabouts through the site. Other features, like allowing people to pay online vendors with some sort of proprietary currency, are in the test phases.

A micromanager, Mr. Zuckerberg has cut down on his meeting obligations and now delegates to senior-level staffers so that he can spend more time mulling Facebook's broader, strategic game plan. (Among other things, he's ruminated what the company would do if it had a trillion dollars at its disposal.) He still has the final word on most product decisions and readily abandons concepts a year or more in the making.

'A lot of companies can go off course because of corporate pressures,' says Mr. Zuckerberg. 'I don't know what we are going to be building five years from now. I don't know what we are going to be building three years from now.'

That luxury, of being light on one's corporate feet, is partly what he fears he may have to sacrifice by going public. Rather than fix their sights on long-term goals, he worries that his staff might become 'focused on an announcement, and how that plays out and whether the stock price goes up,' he says.

Mr. Zuckerberg's hard-charging ways date back to his childhood. At his Ardsley, N.Y., high school, he excelled in the classics. He transferred to Phillips Exeter Academy where he immersed himself in Latin. In college, he was known for reciting lines from epic poems such as 'The Iliad.' His mother called him 'Princely,' say people familiar with his upbringing.

In the company's early days, Mr. Zuckerberg had an artist paint a mural evoking kids taking over the world with laptops. He ended meetings by pumping his fist in the air and leading employees in a chant of 'domination.' (The ritual was in jest, say people familiar with the matter, and he dropped it after executives said it made him seem silly and that competitors might cite it as evidence of monopolistic goals.)

More recently, Mr. Zuckerberg-who himself is the subject of a forthcoming feature film-has used movie lines to cue employees that they are engaged in something greater than getting rich.

At a meeting last spring, Mr. Zuckerberg quoted from the movie 'Troy' before hundreds of employees crammed into the steamy basement of a Sheraton hotel in Palo Alto. He recounted the scene where a messenger tells Achilles how scared he would be to confront the giant Thessalonian, whom Achilles was preparing to battle. 'That's why no one will remember your name!' Zuckerberg shouted.