"These professional matchmakers are often important because online information may not be effective enough," Li Song said. "The biggest difference between us and social networking sites like Kaixin001.com and Renren.com is that we target people who specifically want to get married and start families."

These people, he said, have pretty specific ideas about the kind of partners they are looking for, whereas Kaixin001 and Renren are more targeted at general friendship networking.

Li Song said the company's membership list will soon top 30 million people. In 2004 and 2005, Zhenai received US$12.5 million from three institutional investors in the United States, Japan and Singapore. The company declined to comment further on its financial structure or possible listing in China or on an overseas stock market.

Dating websites, which generally decline to give any figures on their success rates, began five or six years ago without any fees for access to their databases. But fees are now common as the online matchmaking industry has grown and matured.

TV stations have also got into the act. Many create special matchmaking entertainment shows where single men and women go on air to see if they strike up some chemistry.

Many websites are offering online registration for these TV shows and provide eligible candidates to TV stations after combing through their personal information data. The tie-up also benefits the websites, which may attract TV viewers to their services.

Beijing-based Baihe.com has a different strategy for its dating game. Of its 27 million subscribers, about 10 percent are subscribers to its matchmaking services, according to Xie Qingqing, a public relations manager at Baihe.

"We charge users for different categories according to what kind of requirements they look for in a mate," Xie said.

Candidates are divided into 16 categories according to an online psychological assessment devised with the help of the Chinese Academy of Social Sciences. It looks at such attributes as entrepreneurial spirit and philosophical beliefs.

Users are charged between 200 yuan and 300 yuan.

Baihe said income from the service last year topped 100 million yuan, after years of spending considerable amount of money on market promotion and user education.

There is no guarantees of success. A Shanghai woman surnamed Dong who works for a German chemical company noted that one has to spend a lot of time online if one really wants to find a partner. She said she dated several candidates but failed to find anyone suitable.

"Although my parents want me to establish my own family, I want to take some time and make my own choice," she added.

One man who unsuccessfully tried to find a mate online told Shanghai Daily that he suspects many "candidates" falsify information about themselves and the dating websites charge more to put a subscriber in contact with more glamorous-looking prospects. Scams in the industry are not unknown.

The China Marital Status Report said more than 90 percent of the men interviewed thought women should get married before the age of 27, and 32 percent of them put the prime marriage age at between 20 and 24.

Women, on the other hand, tend to prefer older men. More than 50 percent of female respondents said men should marry between 28 and 30 when they have established a stable career and draw a respectable income.

Divorced people, too, often turn to online sites for matchmaking help. Often they are forced to pay higher fees.

When dating service subscribers get discouraged with results, they tend to abandon a website and may bad-mouth it. The trick is to engage them in other services to keep them coming back, iResearch Inc pointed out in an industry research report.

"The number of target users of matchmaking websites is limited, and obviously they will no longer use the websites after they find a spouse," said Xue Shengwen, an analyst at CIConsulting, a market research firm.

Such websites will need to penetrate further into second- and third-tier cities to attract more potential users and expand their membership base, Xue said.