Business networking site LinkedIn appeared to have been blocked in some parts of China, the company said.
No explanation was given for the move, which LinkedIn is still investigating.
However, it comes amid a renewed clampdown on internet discussion groups and micro blogging sites by authorities in Beijing.
Shortly before the site went offline, one user set up a forum, discussing the idea of a "Jasmine Revolution" in China.
The phrase has been used to describe the popular revolts taking place across Egypt, Tunisia, Libya and several other countries.
Over the weekend, a number of pro-democracy demonstrations were held across China, with police making a handful of arrests.
The protests are thought to have been organised in response to calls made on the website Boxun.com, access to which is banned inside mainland China.
Shortly afterwards, a LinkedIn user named Jasmine J created a group called Jasmine Voice.
In one posting, they wrote: "OMG, some pro-democracy fighters really did something here after the triumph of Eygpt".
However, the message does not appear to be strongly for or against a Chinese revolution. BBC News
