The most popular paid sites are hobby and entertainment ventures that provide activities such as gaming, tracking down old classmates and sending greeting cards, according to a survey of 121 publishers by Intermarket Group's Content Matrix tracking service.
The leading site, South Korea-based NCsoft said that as of June, it had 4 million subscribers who pay for its multiplayer game. NCsoft was followed by Classmates Online, which puts high school alumni in touch with each other and claims 1.6 million subscribers. American Greetings, which operates online card sites such as eGreetings.com and Blue Mountain, ranked third with 1.4 million subscribers.
Traffic to the top sites makes up just a tiny portion of the estimated 80 million people online in the United States alone, but the research group expects the numbers to grow.
"Although the majority of Internet users may indeed be unwilling to pay for online content at this point, tremendous opportunities still exist," David Strassel, editor of The Content Matrix service, said in a statement.
According to the study, people were also willing to pay for ConsumerReports.org, with 880,000 subscribers, and for material from RealNetworks and Dow Jones, which claimed 700,000 and 640,000 subscribers, respectively.
, another of the few profitable Web ventures, also showed up among the top 10 subscription services on the Web. Match.com, which posts personals on the Web, has signed up 527,00 people.
Intermarket Group said Yahoo and Lycos would have ranked in the top 10 if those companies had released their subscriber numbers.