Jeremy Stoppelman

Jeremy Stoppelman was on a conference call with venture capitalists when an assistant slipped him a note: "Steve Jobs is on the line."

Stoppelman quietly left the room at Yelp headquarters in downtown San Francisco. It was January 2010, and Google wanted to buy Yelp, the online, crowd-sourced review site. On the phone, Jobs urged Stoppelman, who revered the Apple chief as a visionary, to "stay independent and not sell out to Google." Jobs was not a fan of Google and had accused the search giant of stealing Apple's smart-phone and tablet technology.

"At that point, we had already turned down Google," Stoppelman said. "But Steve liked Yelp and wanted to make sure about Google. It was a moment where I said, 'This is crazy. What just happened?' " For Stoppelman, who is 34 and co-founded Yelp in October 2004, the crazy moments have only continued. After his company went public this spring, when the young entrepreneur pushed the button to ring the opening bell on the New York Stock Exchange, Stoppelman received another call - this one from President Obama, congratulating him.

Today, Yelp has a market capitalization of about $1.3 billion, and Stoppelman's 11 percent stake is valued at more than $145 million. The company, which started in San Francisco as a vague idea about "local," now has 70 million unique monthly visitors, and has expanded to 17 countries. Stoppelman is an undisputed junior titan of Silicon Valley. Sought-after nerd

He also has the canonical startup story. He was the kid who loved to tinker, who inadvertently blew a few things up and charred the walls with his experiments, who learned programming in middle school, earned his bachelor's degree in computer engineering, and then headed west - arriving in San Francisco at the start of the dot-com boom. He was the kid who became a sought-after nerd and was - after his second job out of college - given $1 million to sit around a SoMa loft with a dozen people and a dog and dream up The Next Big Thing.

"The rule in the incubator was that we'd play around and come up with crazy ideas," said Max Levchin, a Ukraine-born computer scientist who co-founded the online payment system PayPal, where Stoppelman worked as his second job out of college. "It was a hacker commune, and the idea was to build great products."

Levchin, whose PayPal was sold to eBay for $1.5 billion in 2002, remembers the day Stoppelman and another former PayPal engineer, Russ Simmons, landed on the concept that would become Yelp. "It was my 29th birthday, and we were at the Slanted Door in the Ferry Building," Levchin said. "Jeremy and Russ had been talking about doing something with local review or local search and were asking questions like: How do you get your friends to help you find the best plumber or doctor or nicest restaurant close by? Over lunch, I could see Russ and Jeremy at the other end of the table just scheming. After lunch, they said they thought they'd figured it out." Ranking of businesses

Returning to the incubator on Mission near Third Street, Levchin listened as Stoppelman and Simmons explained their inchoate idea of an "e-mail type of product where you ask your friends to help you come up with a ranking of businesses."

"I thought it might work, but it might not," Levchin said. "I backed them because I believed in Russ and Jeremy. Russ is an amazing developer and engineer, and Jeremy is just really smart and really tenacious, with a lot of good stubbornness. Their idea was good, but of course it was not what Yelp ended up being, which is very common with startups."

Elon Musk, another PayPal founder, said he always considered Yelp a cool idea. Musk had done something similar with a company called Zip2, which he founded after dropping out of Stanford graduate school to provide local online content to news organizations.