Beijing beefs up its battle against 'vulgar' sites

The launch of the Green Dam campaign is just the latest step in China's war on "vulgar content" on the Internet in a bid to better protect minors.

A drive this year targeted at websites that tote erotic or violent images has already seen 10,000 closed down.

And since 2003, all visitors to Internet cafes, or wangba, have been required to provide their names and proof of ID before gaining access to a machine.