In China, that model may fare better than analytic tools or paid accounts for corporate users. Chinese microblogs do not yet have enough people talking about brands to offer valuable analysis of user discussions to businesses, said Sam Flemming, founder and chairman of CIC, an Internet word-of-mouth research company in Shanghai.
Twitter could offer that service, Flemming said. But microblogs in China are competing with other online forums where users already go to express their thoughts. The most common, bulletin board systems, are sometimes specialized around topics like cars or basketball and already have the discussion level needed to interest a company, he said.
"The challenge is, there are already so many places to talk," he said.
China still has a huge sea of Internet users that microblogs could tap. Over 120 million people, or one in three of China's Web users, currently use social-networking sites, according to the country's domain registry agency. Half of those users post microblog entries online at least once a day, the agency says, though that figure likely includes messages like status updates on Facebook.
Zuosa, Plurk and sites like them are currently focused on building a user base more than bringing in revenue. Chinese microblogs will need time to start turning a profit.
"I think it will take three to five years," said Mou of Zuosa. "You can only make money after reaching a certain size."
Sign up for Computerworld eNewsletters.