Twitter gave as examples of restrictions it might cooperate with “certain types of content, such as France or Germany, which ban pro-Nazi content.”

A Twitter spokeswoman declined to elaborate on the blog.

“Starting today, we give ourselves the ability to reactively withhold content from users in a specific country while keeping it available in the rest of the world,” the Twitter blog said.

Twitter’s decision to begin censoring content represents a significant departure from its policy just one year ago, when anti-government protesters in Tunisia, Egypt and other Arab countries coordinated mass demonstrations through on the social network and, in the process, thrust Twitter’s disruptive potential into the global spotlight.