What You Like.(Business)(Cover story)

Byline: Jessica Bennett; With David Freedman

The goal of social search is to combine Facebook's personal touch with Google's speed.

Search engines tamed the internet when they came out a decade ago, but Gen-Z surfers are growing up on social-networking sites like MySpace and LinkedIn. The advantage of these places is that they're at the same time vast and personal. According to market-research firm the Yankee Group, 13- to 17-year-olds are almost as likely to have visited a social-networking site in a given month as to have conducted a search. Need a yoga instructor? Ask your friends on Facebook. Looking for a pet groomer? MySpace will hook you up.

Entrepreneurs and Internet firms are trying to make this search for personalized information easier by extending the wiki model of collaboration. "If I'm looking for a movie, I want to know what movies my friends liked, and if I want to buy a sofa I'd rather buy it from a friend of a friend than a stranger," says Esther Dyson, a computer-industry analyst and investor. "The successor to Google is more likely to be Facebook than another search engine."

Hundreds of social search sites are groping for a winning formula, but none has been able to develop a critical mass of users. They range from shared bookmarking sites that let users "tag" content with descriptive labels to sites that use both humans and computers to sift information. At PreFound, users submit clusters of Web sites they think would appeal to like-minded people: a user looking for info on spas in California, for example, would get sites other users recommended -- and as an incentive, the largest contributors get a slice of PreFound's advertising revenue.

Other services appeal to companies or ...