Matt Cohler was employee No 7 at Facebook. Adam D'Angelo joined his high school friend Mark Zuckerberg's quirky little start-up in 2004 - and became its chief technology officer. Ruchi Sanghvi was the first woman on its engineering team.
All have left Facebook. None are retiring. With lucrative shares and a web of valuable industry contacts, they have left to either create their own companies, or bankroll their friends.

With Facebook's public offering in mid-May, more will probably join their ranks in what could be one of Facebook's lasting legacies - a new generation of tech tycoons looking to create or invest in, well, the next Facebook.

"The history of Silicon Valley has always been one generation of companies gives birth to great companies that follow, " said Cohler, who, at 35, is now a partner at Benchmark Capital, and an investor in several start-ups created by his old friends from Facebook. "People who learned at one set of companies often go on to start new companies on their own. "

"The very best companies, like Facebook, " he continued, "end up being places where people who come there really learn to build things. "

This is the story line of Silicon Valley, from Apple to Netscape to PayPal and now to Facebook. Every public offering creates a new circle of tech magnates with money to invest. This one, though, with a jaw-dropping $100 billion valuation, will create a far richer fraternity.

Its members will be, by and large, young men, mostly white and Asian who, if nothing else, understand the value of social networks. And they have the money. Some early executives at Facebook have already sold their shares on the private market and have millions of dollars at their disposal. Cohler, for example, is at the centre of a complex web of business and social connections stemming from Facebook.

In 2002, barely two years out of Yale, he was at a party where he met Reid Hoffman, a former PayPal executive who was part of a slightly older social circle. The two men "hit it off", as Cohler recalled on the online question-and-answer platform, Quora (which was co-founded by D'Angelo ). He became Hoffman's protege, assisting him with his entrepreneurial investments, and following him to his new start-up, LinkedIn. Then, Cohler joined a company that Hoffman and several other ex-PayPal executives were backing: Facebook.

Cohler stayed at Facebook from 2005 to 2008, as it went from being a college site to a mainstream social network. One of his responsibilities was to recruit the best talent. Cohler left the company to retool himself into a venture capitalist. He has since been valuable to his old friends from Facebook.

Through his venture firm, Cohler has raised money for several companies founded by Facebook alumni, including Quora, created in 2010 by D'Angelo and another early Facebook engineer, Charlie Cheever. Other companies include Asana, which provides software for work management and was created in 2009 by Dustin Moskovitz, a Facebook co-founder;and Peixe Urbano, a Brazilian commerce website conceived by Julio Vasconcellos, who managed Facebook's Brazil office.

Cohler has put his own money into Path, a photosharing application formed in 2010 by yet another former Facebook colleague, Dave Morin. Path is also bankrolled by one of Facebook's venture backers: Greylock Partners, where Hoffman is a partner.
And he has invested in Instagram, which was scooped up by Facebook itself for a spectacular $1 billion. "Thrilled to see two companies near and dear to my heart joining forces!" Cohler posted on Twitter after the acquisition.

Instagram clearly was a good bet;it is impossible to say whether any of the other investments Cohler or other Facebookers are making will catch fire or whether the start-ups they found will last. Certainly, there is so much money in the Valley today that start-ups have room to grow without even a notion of turning a profit.

Sanghvi, one of the company's first 20 employees, married a fellow Facebook engineer, Aditya Agarwal. Zuckerberg attended their wedding in Goa, India.

With her husband and a third engineer from Facebook, Sanghvi, now 30, formed in 2010 a technology infrastructure company, Cove. It was recently acquired by the San Francisco-based Dropbox, whose founders she knew socially. The Facebook network is vital to her, she said. D'Angelo has become a sounding board for Cove. She has invested her own money in her friend Morin's company, Path. "It's extremely useful to have that network, not just for tangible things like funding and talent but also emotional support, " she said. "Just having those friends has been incredibly important. "

For a glimpse of what may happen after Facebook goes public, consider the millionaires created by Google's public offering in 2005. Overnight, these young men, most in their 20s and 30s, made so much money from Google shares that they never had to work again.