The San Francisco-based microblogging giant said it made the change in an effort to comply with local limits on expression in some foreign countries.
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Twitter has been used to spread messages of dissent and organize government opponents in several countries in recent years. The Chinese government has blocked Twitter, and at the height of protests that eventually brought down Egyptian President Hosni Mubarak last January, Egypt also blocked the service.
Twitter has defended its role in helping protesters in the Middle East and other regions organize themselves and spread unauthorized messages within and beyond their countries. But it now has the ability to comply with local standards by blocking tweets from users just in the country in which they are banned. Those messages would be visible to Twitter users elsewhere in the world.
If Twitter does remove a tweet, users in the country in which it was removed will see a grayed-out tweet in their timeline that says a message from an identified user has been withheld.
Through an expanded partnership with Chilling Effects, a project that tracks constraints on online content, the company also will publish requests to withhold content.
"As we continue to grow internationally, we will enter countries that have different ideas about the contours of freedom of expression," the blog said. "Some differ so much from our ideas that we will not be able to exist there. Others are similar but, for historical or cultural reasons, restrict certain types of content, such as France or Germany, which ban pro-Nazi content."
The company said it hasn't used the new capability yet.
"We try to keep content up whenever and wherever we can, and we will be transparent with users when we can't," the blog said.