Last week alone, two separate groups--the National Hockey League, and a consortium of political operatives including Joe Lockhart, President Bill Clinton's former press secretary and Matthew Dowd, chief strategist for Bush-Cheney 2004--said they were preparing to roll out social networking sites. The NHL networking site is already in a public beta, while the upcoming political networking site, HotSoup, will launch in October.

But some industry observers are wondering whether social networks built around shared interests can gain steam at even a fraction of the pace of MySpace, which commands a higher market share of visits than Yahoo Mail or the Yahoo home page, according to Hitwise.

Aaron Cohen, CEO of Bolt Media, which runs social networking and content sharing site Bolt.com, said that online social networks are the realm of the younger generation. For that reason, he's uncertain whether they'll flourish in niches like hockey and politics, which appeal to a broader age range. "Social media really, really skews young, for now," he said, adding: "If you ask most people who are over 30 if they're member of a social network, they'll say no." Political consultant Michael Bassik agreed that there may not be a big demand for a political social networking site--especially one that purports to cut across party lines. "If you look at the partisan breakdown of the blogosphere, Democrats tend to read left-leaning blogs, and Republicans tend to read right-leaning blogs. People go to political Web sites to have their views confirmed, not questioned," he said.

Bassik likewise said that social networking was a relatively young phenomenon, and may not appeal across the board to politically interested people--something that could be a barrier to the site's mission of bringing people together across political divides. "There's still a large demographic divide among those who use social networking tools to communicate and those who don't, and while this may appeal to younger politically motivated individuals, I'm not sure that it would take off among older political network," he said. "Maybe it's a fun Web site, but does it serve a grander purpose in terms of decreasing partisanship or at least the negativity that has divided the country among party lines?"

Other recent niche social networking sites to launch include MommyBuzz.com--which rolled out last month and offers mothers and prospective mothers places to discuss motherhood, maintain blogs, and buy and sell "mommy gear"--and MOG, aimed at music lovers, which also went live last month.

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