A Chinese rival of Wikipedia that also lets users join groups and chat as they might on Facebook has drawn on those social elements to pull ahead of its competition.
Hudong, which means "interaction" in Chinese, has become the largest wiki-based encyclopedia in the language since its founding in 2005, said company CEO Pan Haidong.
"We want to be the Chinese Wikipedia," Pan said.
Hudong has 3 million articles written by users, more than Wikipedia's count in English. The articles cover topics from astronomy to popular television shows, and the company expects their number to double in the next three years.
But Hudong is also a social-networking site. Users can chat in forums and join groups of people with shared hobbies, like bicycle riding or watching movies. The home page features top-ten lists and links to popular articles. Fan groups dedicated to celebrities like Taiwanese pop star Jay Chou and Jet Li, a Chinese actor, are especially popular, Pan said.
Hudong also awards work on articles with points, which users can spend to "purchase" articles and enter them into popularity duels with other entries, Pan said.
The Web site may eventually allow users to buy virtual items with real-world currency, just as Facebook users can charge their credit cards to send each other virtual gifts. Hudong users could pay, for example, to dress up the avatars that represent them on the site, Pan said.
Hudong has twice the number of articles offered in the online encyclopedia run by Baidu, China's far-dominant search engine.
Wikipedia, a would-be competitor long blocked from viewers in China, still suffers from spotty accessibility. Entries on most sensitive topics will not load in the country.
Content on Hudong appears to be monitored as well. There is, for instance, no entry on Falun Gong, a spiritual movement Beijing has banned as a cult, and Hudong's article on Tibet does not mention any calls for the region's independence.
But when asked whether Hudong faced censorship, Pan said the government is more open than many people think. Discussion in the site's forums can be free-ranging, he said.
The Internet is heavily patrolled by Chinese government censors. Content that could be deemed sensitive or graphic often disappears from Web sites soon after posting.
Hudong uses different wiki software from Wikipedia's MediaWiki. Hudong's in-house software, called HDWiki, is also used on 10,000 other Chinese Web sites and internally in many companies, Pan said.
Hudong aims to become profitable next year, drawing revenue from advertising and from paid support services the company plans for HDWiki, which is open source and free to download, said Pan. The wiki software was the first developed in China, he said.
Hudong's wiki software has helped it grow. Videos and Adobe Flash applications appear more often on Hudong than on Wikipedia because it is easier to incorporate multimedia in the Chinese wiki, said David Wolf, CEO of Wolf Group Asia, a Beijing technology consultancy.
It makes sense to offer social networking on a wiki, software that is social by nature, Wolf said.
But making money could be the biggest challenge for Pan's site, he said.
"While he's got a terrific idea, he's going to have a challenge selling it," Wolf said.