Beijing Tightens Cyber Controls

China is launching its strongest official measure yet to quell electronic expressions of discontent, clamping down on its versions of Twitter that have increasingly fueled once-rare protests and threaten to undermine its leaders' firm hold on power.

In the name of defending Chinese cyberspace against "harmful information," the Beijing city government announced new rules likely to chill a raucous national conversation on services like Sina Weibo, to which Chinese users are flooding to share brief text messages, photos and video. Officials will require users who post so-called microblogs to register their real names with the microblogging services—to be verified by government authorities—sweeping away the anonymity that has helped cloak dissidents online. The new rules also ban the posting of state secrets and material that could hurt national security, as well as posts that spur ethnic resentment, discrimination or rallies "that disrupt social order," the state-run Xinhua news agency said. The rules didn't mention penalties. The move represents a potential turning point as the Internet has become an increasingly disruptive force for China's leaders ahead of once-a-decade transition next year, when China's top two leadership positions will change hands.