SAN FRANCISCO -- The great white whale of social networks just topped 1 billion members, yet Facebook is getting even more competitive company.

Three more contenders surfaced last week in attempts to take a nibble out of Facebook, whose broad audience and services may not appeal to consumers interested in specialized content.

Pheed and CyPop launched, and Myspace made its comeback. Each promises a unique approach to social networking. But some analysts fear the proliferation of such sites could end in them cannibalizing each other.

There is a method to the madness of small companies attacking Facebook's flanks, media experts say. The social-networking giant may find itself in the same predicament as TV networks, Internet portals and general-interest magazines: too big, and susceptible to narrower, special-interest media.

"Niche social networks won't force Facebook out of business, but they could cut into the amount of time people spend on Facebook," says Jeff Lillibridge, vice president of social media at digital-marketing firm Phizzle.

The trio of new entrants join a long list including photo-rich Pinterest; Path, a tight-ringed place for close friends; ArtStack for art purists; Luluvise for women; SportsYapper and Heckler Sports for fans; and Viddy for video.

Pheed lets users share texts, photos, videos, voice notes, audio clips and live broadcasts. "On Pheed, you express yourself," says OD Kobo, CEO of Pheed. "The Web is not only about my friends."

CyPop connects people through their common interests, such as yoga, rather than the virtual circles of friends and family that make up most social-networking sites.

An old mainstay, Myspace, now co-owned by Justin Timberlake, has been re-positioned as a social network for artists and their fans.

Despite the rise of small, focused social networks, Facebook and its 1 billion members remain in an enviable position, says Sameer Patel, general manager of enterprise social software at SAP.

Americans spent an average of nearly seven hours on Facebook in August -- more than three times the runner-up, Yahoo -- according to Nielsen.

"Big is OK," Patel says. "Facebook is the formidable, unified identity of social networking. They are most people's main base, and secondary social networks complement them nicely."

But the glut of new social-media networks could overwhelm consumers and turn into media overload, says Esteban Kolsky, founder of ThinkJar, an advisory service for customer strategies.

"There are too many, and none have shown value yet," Kolsky says.

"There is only so much consumers can absorb," Kobo adds. "They can't do all their social-media tasks across several services. Who has time?"

USA Today