Ever found pornographic photos or ads in your e-mail inbox?
If so, you were a victim of one of the 10 "worrying trends" in the Chinese online community spelled out by Wang Chen, minister of the State Council Information Office, at an Internet media forum in Chongqing on Friday.
Other worrisome practices include spreading malicious online rumors, stealing personal financial information and the false online marketing of products. The trends are "posing a major challenge" to regulating the country's expanding online community, Wang said.
Efforts must be made to increase supervision of the Internet and enlist the help of Internet stakeholders to keep objectionable elements out of cyberspace, Wang said.
There are no major differences in offline and online activities under the law but the anonymous nature of the Internet makes it harder for online activities to be regulated, Qiu Lufeng, a professor from Nanjing University's law school, said.
"The online community is so large that users can hide their real identities, making it hard to trace behavior to a 'real' person. For example, if a person verbally attacks me online, it is troublesome for me to look for or even sue him as I don't know his real name," Qiu said.
The number of Chinese Internet users reached 253 million in June, according to figures from the China Internet Network Information Center (CINIC), making it the largest such group in the world.
A CINIC survey of 16,000 Web users conducted in July found 35 percent of those polled were "dissatisfied" with the credibility of Internet sources, with less than 15 percent of respondents finding online information "authentic".
"The Internet is becoming more elaborate and popular, but it is also becoming more dangerous," Pi Xing, 23, a teacher from Jiangsu province who spends at least four hours a day online, said.
"It's horrible how one's personal information can be obtained and shown for all to see," she said.
A number of groups are making it their business to help keep unwanted elements off the Internet.
A website under the China Internet Information Center, Y.china.com.cn, launched a campaign in May to help keep rumors about the Sichuan quake off the Internet, with false information such as times of aftershocks and fake donation drives being weeded out, Song Gang, the portal's assistant director, said on Friday.
More than 150,000 people and 563 websites have so far signed up to help in the latest cleanup, Song said.
Nearly 1,000 people have also volunteered to help the website by collecting misleading information and fake advertisements, publishing these on the portal as a warning, Song said.
"The Internet can't stay clean without everyone's effort," Pi said.