Internet surfers at a cybercafe in Beijing. Lists of names from WikiLeaks cables circulate on websites and popular microblogging platforms.

A blogger and social media commentator who compiled meticulous daily lists of protests in China, making the results public via Google, Twitter and Weibo, has been incommunicado for nearly a week, along with his girlfriend, rights activists said on Tuesday.

Former migrant worker Lu Yuyu, who went by the Twitter nickname @wickedonnaa, called his online operation "Not the News," in a nod to the widespread censorship of "sensitive" stories of mass protests by the ruling Chinese Communist Party and the media outlets under its control.

"I asked a friend of his, and he said Lu hasn't updated his information online for about four days," a friend of Lu's who gave only the surnamed You told RFA on Tuesday.

"He would normally usually post at least once a day to Twitter or Weibo, so we'd usually have daily updates from him," he said.

You said it is possible that Lu had recently traveled to the rebel village of Wukan in southern China's Guangdong province after protests flared there over the weekend following major clashes in 2011.

"I'm thinking that perhaps he went to Wukan [to cover the protests] and got detained there on arrival," You said.

He said the sort of data Lu compiled, which last year including details of more than 30,000 "mass incidents" not widely reported in China, could easily have made him a target.

But he said Lu was typically secretive, communicating very little of his whereabouts to family and friends.

Detained at any time

Sichuan-based rights activist Huang Qi, who founded the Tianwang rights website, said Lu's work could get him detained at any time.

"Reporting this kind of news, as he does, isn't the sort of thing the Chinese government wants to see," Huang said.

"The authorities do everything they can to suppress stories like this that touch on press freedom and the welfare of ordinary people," he said.

Huang said 13 former employees and volunteers at the Tianwang website have been jailed for their involvement in publishing the stories of ordinary people fighting for their rights through legal and peaceful means.

Online writer and activist Wen Yunchao said Lu has reported, compiled and made archives of popular protest in China going back four or five years.

"The statistical work Lu did wasn't just about the quality or amount of his data; it was really exceptional," Wen said.

"Through Lu's statistics, it's possible to get an instant look at mass protest in China; it's a unique window on Chinese society," he said.

‘Coercive measures’

Liu Feiyue, who heads the Hubei-based Civil Rights and Livelihood Watch, said he believes Lu has been detained or placed under "coercive measures" by the authorities.

"He used [all kinds] of methods to disseminate news about people fighting for their rights," Liu said. "Most of them had a bearing of people's livelihoods, for example, forced evictions and demolitions, or the protests in Wukan."

"The authorities won't let any of that go unpunished; the environment for [activists] in China is getting really bad," he said.

Reported by Qiao Long for RFA's Mandarin Service, and by Wong Lok-to for the Cantonese Service. Translated and written in English by Luisetta Mudie.