Burlington, Mass.-based Burst Media found that only 19.2 percent of web surfers have ever visited a social networking site.
The survey, which polled 9,200 surfers on their web habits, found that of those respondents, slightly more than half (50.5 percent) actually registered and joined these sites.
Men were slightly more likely than women to say they have visited a social networking website (21.7 percent vs. 16.7 percent). But women are more likely to register and join (53.3 percent vs. 47.9 percent).
Those under the age of 24 are most likely to say they've visited a social networking site, the study said, with 26.8 percent saying so. Among those 55 and older, 10.4 percent said they have visited a social networking website.
"Social networking sites, such as Friendster and Tribe.net, create communities by encouraging enrollees to invite friends to join, so friends bring friends who bring friends, and a virtual social community has been created," said Chuck Moran, Burst Media's market research manager.
But Internet analysts are skeptical of the business models.
"There's no significant business here on the social networks side – they cannot exist as stand-alone businesses. As part of a portal, they may actually work out great," said analyst Nate Elliott of Jupiter Research, which issued a report several months called, "Social and Business Networks: A Phenomenon in Search of a Business Model."
"There's only one thing that people want to do with social networks, and that's looking for dates and romantic relationships,” Elliott said. “Everything else people want to do with social networks is free."
Jupiter's own report found that only 32.7 percent of online users are interested in using online social networks, and only 6.2 percent of online users say they want to use online social networks to find dates. It also found that 21.3 percent look for dates on dating sites.
"Yahoo owning a social network could bring Yahoo value," said Elliott, who noted that he sees more value in professional networking sites, such as Ryze.com and LinkedIn.com. "Their customers can expense or deduct the charges."