In early August, major news portal websites have implemented real name registration. Netizens who want to post comment online have to fill up a registration form that collect data on user's real name, ID card number, contact phone and address. New York Times reported:

But in early August, without notification of a change, news portals like Sina, Netease, Sohu and scores of other sites began asking unregistered users to sign in under their real names and identification numbers, said top editors at two of the major portals affected. A Sina staff member also confirmed the change.

The editors said the sites were putting into effect a confidential directive issued in late July by the State Council Information Office, one of the main government bodies responsible for supervising the Internet in China.

Below is a standard registration form screen captured from one of the news portals, Sohu.com (via GFW blog):

Although netizens can fool the system with fake IDs and names, the registration will likely have a chilling effect, as Rebecca MacKinnon pointed out:

Even without real-name registration it's not so hard for the police to track somebody down if they really want to – as long as that person isn't using an anonymity tool like Tor and being extremely careful about their general online security. With growing numbers of Internet users being detained and prosecuted on charges of “spreading rumors” lately, even though the real-name registration system is far from thorough or perfect, it's likely to have a chilling effect.