Some activists question the value of such efforts, saying that the calls for widespread protests have accomplished little except to provoke the government into arresting dozens of activists since February.

“It’s an admirable attempt at free expression, but we have not seen any sudden change come of it,” said Pu Zhiqiang, a leading human rights lawyer and advocate of democratic reform in China. “Instead, we’ve mainly seen the Chinese Communist Party frighten itself over it. So it’s hard to see the significance of it in the short term.”

The very first call for a Jasmine movement was broadcast from a Twitter account, which was quickly overwhelmed by suspect messages and subsequently shut down, dissidents overseas said. The call was taken up by Boxun, a Chinese-language site run out of North Carolina, before that site too suffered a massive cyberattack in late February. Those attacks continue to cripple the site, said its editor, who is known by the pseudonyms Wei Shi or Watson Meng.

After the Boxun site was attacked, the New York blogger who calls himself Gaius Gracchus connected with activists in China to publish molihuaxingdong.blogspot.com, or Jasmine Movement, a simple blog on Google’s blogger platform, to keep the momentum going online. His role was first reported by The Associated Press.

The blog has registered more than 600,000 visitors, more than half of them from within China, and his group’s e-mail list includes more than 3,000 names.

Sitting at a spare black desk in his girlfriend’s Morningside Heights apartment, where he lives, Gracchus said that his group protects itself against malicious viruses by using Linux-based operating systems and by opening e-mail attachments using iPads, both of which are less susceptible to them. To secure his communications, he employs a Google application that sends a unique code, which changes every minute, to his mobile phone so he can log into his e-mail.

Such commercially available security precautions are not the stuff of cloak-and-dagger cyberwarfare, and Gracchus readily admits putting his faith in Google. “If Google falls, we would worry about our safety, but we believe that Google has better engineers than the Chinese government,” he said.