SUNDAY PROFILE - Start-up whiz takes on new challenge - Joe Kraus, co-founder of Excite and JotSpot, guides Google's efforts in social networking.

His assignment: Help run a team that would figure out how to match the runaway popularity of Facebook Inc., which has been stealing Google's spotlight.

The company tapped the bespectacled veteran of two start-ups because it figured he could harness the experience and energy needed for a showdown that could determine the course of the Internet's social networking revolution.

Along with fellow project leaders Graham Spencer and David Glazer, Kraus assembled several dozen engineers, many of them former entrepreneurs, and housed them within shouting distance of one another to simulate the hothouse environment of a high-tech start-up.

The engineers came up with OpenSocial, an alliance of social networks and software developers designed to help people connect no matter where they go on the Web, whether to Craigslist.org to see what friends are buying and selling or to Ticketmaster.com to see what concerts they're attending.

"If the Web is more social, and therefore more engaging, that means everyone will spend more time there and have more things to do, which benefits Google," Kraus says. "Google makes money when people spend time on the Web."

Members of OpenSocial -- which include MySpace, Bebo and LinkedIn -- pledged when they signed up last month to make it easier for developers to create software features across an array of social networks. The alliance is more concept than reality right now, but already it's given a boost to the vision of an open social web, where users can take their friends with them rather than having to build and maintain contact lists on different sites, says Joseph Smarr, chief platform architect of social networking site Plaxo, one of Google's partners in OpenSocial.

"Google showed that open is possible, desirable, tangible and good for business," Smarr says.

The company has plenty of self-interest at stake. Tens of billions of dollars in online advertising are expected to shift to social networks in coming years. Although the effectiveness of reaching consumers on these networks is not proven, marketers are intrigued by the prospect of feasting on the wealth of personal information that users volunteer.