China's turnaround comes as public outcry over the Green Dam Web filtering software struck a nerve both inside and outside China. Last week, the Chinese government mandated that as of July 1, all PCs sold in the country must have the Green Dam software to block pornographic and violent Web sites. The public fought back, claiming the software could also block users from viewing political content and censor other content. Some opponents also contend that the software can create security vulnerabilities that can be exploited by hackers.

An official with China's Ministry of Industry and Information Technology who wouldn't reveal his name told The Associated Press that the use of the Green Dam Youth Escort software is "not compulsory."

The ministry official added that while all computers sold on the mainland will feature the filtering software, individuals are free to decide whether they use it. PC makers will also be required to tell government officials how many computers they have shipped with the software, which was made by a developer contracted by the Chinese government. Solid Oak Software, a U.S. application vendor, however, alleges the makers of Green Dam stole some of its code to make the controversial filtering software.

While China stands firm that the software is designed to block violent and pornographic content, some users have said it also prevents access to other topics including homosexuality, images of comic book characters and mentions of the Falun Gong spiritual group, Chinese media have reported. The software has also blocked images of pigs, confusing them with naked human flesh, The Associated Press reported.

Chinese bloggers, along with lawyers and other civil rights proponents, have been vocal in their opposition to the Green Dam Youth Escort software, which is the most recent attempt by the Chinese government to maintain control over its citizens' Internet viewing habits.

Opponents also contend that Green Dam is China's most intrusive Web filtering tool because it censors right on a user's personal hard drive and can also force offline programs like text editors to crash if a banned phrase is typed.

China has already spent more than $5 million on the Green Dam software. China also has the world's largest population of Internet users, estimated at more than 250 million.