Within a few years of its birth in 1993, the Web was already so vast that the old-fashioned, human-centered ways of finding information--asking a librarian, browsing the collection, or even consulting a human-compiled Web catalog such as the early Yahoo--were rendered useless. Google won millions of users starting in 1998 because its popularity-based PageRank algorithm seemed to magically and unerringly produce the Web pages most relevant to a user's query.

But the Web has grown orders of magnitude bigger since the founding of Google, and neither the company nor its competitors have come up with new automatic search algorithms as seemingly magical or game changing as PageRank. Now some entrepreneurs believe it's time to replace the algorithmic search engine with humans.

ChaCha, a free advertising-supported service launched last year by former MIT AI Lab research scientist Scott Jones and software entrepreneur Brad Bostic, doesn't exactly give up on the concept of computerized search. Web wanderers in search of answers are free to settle for the algorithmic results served up by ChaCha's own search engine. But the site's real calling card is its collection of 29,000 human guides, who earn $5 to $10 per hour working with users in live chat sessions to locate the Web's best answers to their queries.

Web services that tap the brainpower of real humans are all the rage. Many now-familiar sites such as Digg and Wikipedia depend on the "wisdom of the crowd"--users who contribute, edit, and collectively rank information items. But newer ventures depend on individuals. Yahoo Answers, where anyone may submit a question and anyone else may respond, has proved immensely popular, attracting more than 60 million users (despite the varying quality of the site's answers). More recently, Amazon's Mechanical Turk, a marketplace where individuals can earn small amounts for completing "simple tasks that people do better than computers," in Amazon's words, has provoked much discussion among followers of the user-centered Web 2.0 movement.

But for all its fashionability, ChaCha's idea of outsourcing Web searches to human guides has yet to prove itself as a plausible or profitable alternative to self-serve algorithmic search engines. Amazon CEO Jeff Bezos apparently believes in ChaCha's possibilities: this month his personal venture-capital fund, Bezos Expeditions, led a funding round that netted the company $6 million. Yet Jones himself admits that often, ChaCha's guides aren't able to provide users with results surpassing those a conventional search engine might produce.

"About one-third of the time, people are getting what I call the 'magical experience,' where they've tried finding the information in other places, they come to ChaCha, and they're shown something extraordinary and different," says Jones, who is also the founder and chairman of music metadata provider Gracenote. "That's obviously not good enough yet. But it's up from 5 percent of the time just two or three months ago. What gives us hope is the trend line."