MIKE MCCUE, 44
Cofounder, Flipboard

With the possible exception of Angry Birds, no iPad app has been more discussed than the media aggregator Flipboard, which was Apple's 2010 iPad App of the Year. The service, conceived by Mike McCue, a longtime Silicon Valley entrepreneur, and Evan Doll, a former iPhone engineer, emerges from a simple premise: iPad users value aesthetics, and most aggregators are ugly. So when Flipboard pulls from your Facebook, Twitter, and other social feeds, it reshapes the content to read like a magazine, with bold images, headlines that pop, and navigation that mimics page-flipping. Initially, the product generated more interest than the company could handle. "It was way more than we ever anticipated on launch night," McCue explains, "which crashed our servers pretty quickly." But as anyone who's seen The Social Network knows, that's an auspicious beginning. The next step toward world domination: Flipboard for iPhone, expected later this year.

VITAL SIGNS

Year Founded: 2010
Home Base: Palo Alto, California
Number of Employees: 42
Number of Users: 3 million
Estimated Valuation: $200 million

USER DATA

Aesthetic inspiration:
"The front page of the Wall Street Journal. I think it's a work of art. All the news of the entire world is boiled down to one page you can easily scan."

How to keep Flipboard feeds compelling:
"I have a Facebook list called 'Most interesting friends,' which is basically a subset of all of those friends who tend to post really interesting things, not just pictures of their dogs."

Start-ups are like having children:
"I have four kids. By the time you get to your second or third or fourth, you know what really matters and what doesn't really matter. It's very similar with a start-up."

Most obnoxious start-up lingo:
"'What's your exit strategy?' Anybody who goes into a start-up thinking about an exit plan isn't likely to build something of durable value."

Best way to blow off steam:
"Actually, my wife and I just went to Alaska. To have four days where you're totally, totally offline and all you're worried about is not getting eaten by a bear—that was liberating."


CHARLIE CHEEVER, 30
Cofounder, Quora

When you want to dig up some obscure fact, you probably head to Wikipedia. But you won't get any sort of analysis or commentary there. That's why two Facebook expats launched Quora, a question-and-answer network that lets users follow both individual topics and the experts who know the most about them. "There's so much value to be unlocked from everyone in the world sharing everything they know with everyone else," cofounder Charlie Cheever explains. He and partner Adam D'Angelo built a system that allows any registered user to ask or answer any question, a model that has drawn bold-face names like J.J. Abrams (who answers "How do directors conceive and think through monster and action scenes?"), Mark Cuban ("Should NCAA players be paid?"), and AOL cofounder Steve Case ("What factors led to the bursting of the Internet bubble of the late 1990s?"). Got a question for them? Ask away.

VITAL SIGNS

Year Founded: 2009
Home Base: Palo Alto, California
Number of Employees: 24
Number of Topics: 60,000+
Estimated Valuation: $1 billion

USER DATA

The moment I knew this was going to be big:
"One time, when I went to search for something on Google, the first result was on Quora—and it was a really good answer that I hadn't even realized was on our site."

What I learned from working at Facebook:
"Ten years ago, it was mostly just the nerds who were on the Internet. Now my grandmother can work an iPad. To make a competitive product, you have to put a ton of effort into designing a great user experience and simplifying things."

The apps I'm into right now:
"Photo-sharing apps like Instagram and Path. They're really simple, but pictures are so powerful."

How Quora can get very, very personal:
"There was a question about what it was like to be in the World Trade Center on 9/11, and a couple of people who were actually there chimed in. There's no way that I could've found out what that was like without being connected to those people."

One of the biggest compliments about Quora:
"A guy told me that he got a job through our site. He posted some stuff about a company that someone who works there saw. They reached out to him, met up, and eventually offered him a job."

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