The fable of the dropout prodigy is so widely-told in Silicon Valley that it even came back to bite the enfant terrible who inspired it. In a new Q&A in the New York Times, Farhad Manjoo asks 29-year-old Mark Zuckerberg if he's out of touch with teens.

It takes two strains of Silicon Valley folklore to get the point where the CEO of a $148 billion company is being politely nudged out to pasture before his 30th birthday. There's the notion that Facebook's success was due to Zuckerberg's age and phenotype. As Y Combinator founder Paul Graham put it:

"The cutoff in investors' heads is 32," Graham says. "After 32, they start to be a little skeptical." And Graham knew that he had his own biases. "I can be tricked by anyone who looks like Mark Zuckerberg. There was a guy once who we funded who was terrible. I said: 'How could he be bad? He looks like Zuckerberg!' "

Nevermind that WhatsApp, Facebook's $19 billion hope for the future, was built by a pair of industry veterans, ages 38 and 42.

Then there's the tech sector's version of a teenage dream. When the prevailing business model is if-you-grow-it, we-can-monetize-it it's only natural to be concerned about what happens if the hockey stick-shaped graph starts to droop. No one has yet invented a magical new way of making money besides advertising, e-commerce, or subscriptions. Advertisers, because let's be honest it's still mostly advertising when the product is free, like them young.

But the youth complex is more desperate in social networks or apps. Technology evolves rapidly and so does the way it's used. The logic is that any teen is a prognosticator of tech trends, just by virtue of being a teen. Scraps of information about their online habits are greeted in the tech press like the App Oracle of Delphi.

No such slavish attention is heaped on other untapped demographics, like non-white, rural, or foreign users, except for the occasional nod to China and now India. The lesson of the WhatsApp acquisition, however, seems to be all about the latter.

When Manjoo asks whether he gets Facebook's audience, Zuckerberg reframes it as question of growth for a corporation with 1.2 billion users. Then, he points to emerging markets where future Facebook users are not yet online:

Q.

Can I ask one personal question? You're turning 30 this year. And a number of these apps are being used by people who are way younger than that. When you started Facebook you were in the audience of people using Facebook. And now you're not for apps like Snapchat or some of the newer kinds of apps. Do you feel like you are in touch with the audience that's using some of these newer things?

A.

It's not clear to me that when you look at younger folks or older folks that there's any trend of apps starting in one audience and going on to be more mainstream. Pinterest's early users were not tech people and not younger people, and it was very female-centric. Some of these other services might start with teens. But I think Twitter′s early strength wasn't younger folks. One of the companies I think is the most interesting right now is Tesla. People have been trying to do electric cars for years. They realized that they could deliver a very high-quality product if they marketed it as an upscale thing.

Oh, and most people who use Facebook have not been my age through the majority of my time here.

But understanding who you serve is always a very important problem, and it only gets harder the more people that you serve. We try to pay a lot of attention to this by a combination of very rigorous quantitative and qualitative feedback. But if you're serving 1.2 billion people, it's very hard.

And I think the age thing is probably not the biggest one I worry about. I'm focused on Internet.org and how to connect all these people. But my life is so different from the person who's going to be getting Internet in two years. One of the things that we do is ask product managers to go travel to an emerging-market country to see how people who are getting on the Internet use it. They learn the most interesting things. People ask questions like, 'It says here I'm supposed to put in my password — what's a password?' For us, that's a mind-boggling thing.

The old man's still got it! That's the way it should be answered. But rather than whether Facebook can innovate, the question I'm curious about is whether any company with a focus on social interactions will be around in 20 years. If a tech wunderkind is washed up by 30, what is the lifespan of the products and companies they build?

To contact the author of this post, please email nitasha@gawker.com.

[Image via Shutterstock]