Google became one of the world's most important companies virtually overnight by making the best version of something billions of people needed, or were soon to need: a tool for searching the internet. But its unprecedented growth--a 2011 book labeled it "The Fastest-Growing Company in the History of the World"--left Google with an acute need of its own. 

In 2003, a year before it went public, the startup had just 800 employees. By the time of the IPO, that number would be 2,200. In 2008, when Google turned 10, it had 20,000. Now, as Google celebrates the 20th anniversary of its founding, more than 70,000 people work under the umbrella of Alphabet, the parent company created in a 2015 corporate reorganization.

All those people needed leaders. And not just any leaders, but people who could do it in an environment of incessant change and planetary scale. Much attention has been paid to Google's idiosyncratic (and now widely copied) hiring practices. But it was the company's success at reliably turning the supremely talented people it found into elite managers that enabled it to maintain and extend its dominance over two decades -- an eon in internet time. 

In Silicon Valley today, the results of that effort are everywhere. Google veterans have gone on to run some of the biggest internet companies already in operation (Marissa Mayer at Yahoo, Tim Armstrong at AOL/Oath) and launch some of the biggest new ones (Pinterest's Ben Silbermann, Twitter's Evan Williams, Instagram's Kevin Systrom). Facebook COO Sheryl Sandberg, Dropbox COO Dennis Woodside, Asana president Justin Rosenstein, and Taskrabbit CEO Stacy Brown-Philpot are among the many other notable "Xooglers." 

"The people who went through this--it's no surprise they're at where they're at because they have such a breadth of experience," says Jared Smith, co-founder of Qualtrics, which makes customer survey software. He's one of the people he's talking about, since he as a Googler from 2004 until 2010. "The DNA that resulted was pretty special." 

To understand what made Google such a fertile training for leaders, particularly in its early years, I talked to Smith and four other members of the Google diaspora about what they learned under Larry Page, Sergey Brin, and Eric Schmidt, and how the company's unique culture and practices helped make them who they are. 

Think big. No, bigger. No--really, really big.

"Underpromise and overdeliver" is pretty good advice in most corporate settings, but it's the opposite of what leaders were taught at Google. There, overdelivering meant you weren't setting your targets high enough. The mandate from the top down was to be super-ambitious and build in some margin for failure, says Wayne Crosby, co-founder of Humu, a new human resources startup. That philosophy was baked into the way managers handled OKRs (objectives and key results), a method of goal-setting and performance tracking that began at Intel but is now even more associated with Google. "If you're only going to achieve 70 percent of your goal, if you're aiming high, it's still going to be an amazing success," says Crosby. "It's important, in Google lingo, to have those moonshots."

"Google was exceptional at taking a very long view and extrapolating things we believed to be true into the future, and then acting now on those beliefs," says Woodside. He recalls a meeting with Page sometime soon after he joined the company in 2003 as its director of business operations. Hashing out Google's emerging markets strategy, Woodside presented a list of 20 countries he thought Google needed a presence in. "I remember Larry saying, 'You do realize we have people searching on Google in over 190 countries?'" He was encouraged to double the number of countries in his plan. 

"It wasn't about doing 10 percent better," says Brown-Philpot, who arrived at Google around the same time as Woodside and stayed almost nine years. "It was about aiming for the 10X gain, the seeming impossible." So-called "10X thinking" refers to ignoring incremental gains to focus on order-of-magnitude improvements. It's another Google tenet. 

To encourage that kind of ambition, Google employees were given all the money and manpower they could possibly need. "If you happened to end up on one of these teams that's of strategic value, you essentially had unlimited resources," says Crosby. Schmidt, says Smith, always urged his managers to run toward the most difficult challenges rather than try to find ways around them. The message: "Everything you do, figure out how to take on the big, scary computer science sides of it, because that's Google's competitive advantage," he says. 

To lead, you must inspire.

For most of its first decade, even as it grew to thousands and then tens of thousands of employees, Google had an unusual, flat corporate structure organized by job function rather than business unit. (After Page returned as CEO in 2011, he introduced some more conventional elements, although Google still retains a high degree of cross-functionality.) In practice, this meant to get anything meaning done, one had to be able to recruit help from far-flung parts of the company rather than just issuing orders to those further down the food chain. 

That put a premium on the ability to communicate effectively. "How do you get something done when you're depending on other people who don't work for you? You have to reason with them," says Smith. "Everything was an intellectual discussion." "The leaders that succeeded were the leaders that were inspiring," says Margo Georgiadis, who was Google's president for the Americas and is now CEO of Ancestry. The idea that it's the manager's job to inspire rather than the underling's responsibility to follow orders taught humility, she says.  "It's not a culture of stars. It's a culture of highly collaborative, aspirational leaders that are highly networked and interdependent." 

Indeed, anyone who saw themselves as a star at Google was in for a rude shock because the level of talent was so high. "One of the first things we learned as managers was how to deal with employees who were crying in their reviews because they felt like they were failing or they were average and they'd never experienced that before," says Smith. 

Use your words. 

There's a reason Google-speak like "moonshot" and "10Xer" has because standard startup lingo. Even though it's the ultimate culture of engineers, Page and Schmidt appreciated the power of language to inspire people across a huge organization to accomplish huge things. "Larry, in particular, was really good at distilling really big ideas into simple and motivational catchphrases," Woodside says. 

Page also self-consciously identified targets that were at the edge of technical feasibility but easy for even a layperson to understand--goals like mapping the entire world to a one-meter resolution. "I always think about Larry's phrase 'Make the impossible possible,'" says Georgiadis. Another one she borrows is the "toothbrush test" Page uses  to assess the potential payoff of new businesses. "A billion people have to want to do this every day for it to be a great idea." 

Brown-Philpot says it was Schmidt who really schooled her in "the importance of storytelling as a company leader. Eric talks about how great leaders are great storytellers because narrative is how we learn." At TaskRabbit, she makes sure to begin every weekly standup meeting with a story. "The power of a story is to inspire your teams and help them feel connected to the company's mission and vision," she says.