Some Twitter users say they will stop using the service on Saturday in protest of the company’s new rule that allows for content to be blocked in specific countries.

The policy, announced Thursday, on the company’s blog will enable the company to block specific tweets on a country-by-country basis when the content runs afoul of local laws.

Several global companies, including Google and Facebook, already have similar policies to remove content to comply with individual countries’ laws regarding speech — one of the most commonly cited examples of a law like this is Germany’s prohibition against pro-Nazi content. Critics worry that Twitter’s policy will destroy its capability to work as a platform for impromptu social movements, a role it played so prominently during the Arab Spring.

“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 post read, in part. “We have also built in a way to communicate transparently to users when content is withheld, and why.”

Posting messages with the hashtags “#TwitterBlackout” and “#TwitterCensored,” users vowed to let the company know that they opposed the new policy. Several of the tweets were in Arabic.

The company said that as it continues to grow globally it’s had to rethink its policies on free expression. “As we continue to grow internationally, we will enter countries that have different ideas about the contours of freedom of expression,” the post said. “Some differ so much from our ideas that we will not be able to exist there,” the post said.

Demand Progress penned a quick open letter to the company asking Twitter to “keep fighting for and enabling freedom of expression — not rationalize away totalitarianism as a legitimate “different idea.”

Twitter spokesman Matt Graves explained that the company will first notify an individual user when his or her content is withheld. Next, it will post clear notice to users in the country where the content is being withheld. Finally, users outside of the country that asked for the content to be taken down will still be able to see the content.

Twitter said that it created the tool to censor by country in order to prevent having to remove illegal content from its global network. Restrictions will be based on a users’ IP address, and users will be able to select their country though their account settings if Twitter misidentifies their country.

The company said that it has yet to use this new function, and will attempt to let users know when their content is being reactively withheld from a certain country. It says it has taken steps to make sure that the rest of the world will be able to see when tweets are removed from a given country.

The company is also working with the Web site Chilling Effects — a joint project of the Electronic Frontier Foundation and several universities — to post all the takedown notices it receives, whether from copyright holders or from foreign governments. Twitter has already begun posting copyright takedown requests.

Google already uses Chilling Effects to share its takedown notices and also compiles those notices Transparency Report — which many have used as a tool to examine the global Web censorship picture.

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