ALL OF THE FUN LIES IN TRYING TO ANSWER QUESTIONS:

The love affair between tech-industry insiders and Quora isn't just about the payday they foresee for its founders and, in a few cases, themselves. The pull is far deeper, and odder, than that. It's hard to think of any website that has ever inspired this level of personal ardor among entrepreneurs and investors, not just as admirers or enviers but as users. These men and women (mostly men) don't merely spend hours every day, despite their all-consuming work schedules, posing and answering questions on the site; they indulge in rhetoric that floats high above the typical boilerplate about startups changing the world. Quora is "a micro-university," says Chris McCoy, an entrepreneur from Sunnyvale; it's "the modern-day equivalent of the Library of Alexandria," says Ari Shahdadi, a New York-based lawyer who works with startups. Savvy users like them know from personal experience that most companies fail, that new websites flare up and fizzle out like fireworks. And yet they somehow have come to see Quora as far more than just another online venture: It's nothing less than an extended family, a virtual salon, a potential revolution in knowledge.

For that revolution to succeed, Quora will need to achieve something even more implausible. It will need to replicate--in hundreds of communities and fields of expertise far from San Francisco Bay--the same kind of fervent engagement that it has sparked among Silicon Valley insiders. The site has already shown what it can accomplish inside a small biosphere of like-minded people with high IQs and outsize ambitions. That was the easy part. The big question now is: Can Quora really hope to answer everything?

In 2005, The Onion imagined a new product from Google called Google Purge. Its purpose was to delete from our brains any information the search giant could not index. What's the use of harboring private experiences, after all, if they can't be cataloged and accessed via search?

Google Purge was a joke, of course, but buried inside the satire was a kernel of seriousness. Two decades after the invention of the web, there are vast areas of knowledge and experience that are still not online, let alone searchable. Wikipedia, which just recently celebrated its 10th birthday, is astonishing in its breadth and scope, but there's only so much that any encyclopedia, limited to verifiable facts about discrete nouns, can capture within the entirety of human knowledge. On the other end of the spectrum, sites like Facebook and Twitter allow people to describe their lives and to make personal observations, but on such networks it's hard to separate the informed opinion from the pure speculation.

The large expanse between the two approaches--the purely objective and the purely subjective--is the terrain that Quora hopes to occupy. What was it like to live in Silicon Valley in 1998? What goes on neurologically when a song lodges inside a person's head? What should the Winklevoss twins have done to protect their idea for Facebook? Will human consciousness ever be transferable to a computer? Those are questions no encyclopedia could ever hope to answer fully, and yet in each case, there are people who can tackle them with a fair bit of authority. For years, blogs have occupied this territory, but their idiosyncratic and diaristic style has left their insights largely inhospitable to search. By creating an environment for members to post and answer questions, as well as rate the quality of others' answers, Quora is building a searchable repository of information while it also builds a community.

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