Twitter, according to its official description, promises to offer up the "latest information about what you find interesting."

There's now a caveat to that, however: The social media service will offer up the latest information about what you find interesting -- and what your government deems acceptable.

Twitter announced Thursday that the company now has the ability to censor tweets on a country-by-country basis, allowing the popular microblogging site to comply with local governments' request to remove or block certain content.

"Until now, the only way we could take account of those countries' limits was to remove content globally. 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," Twitter wrote in a blog post. "We have also built in a way to communicate transparently to users when content is withheld, and why."

The company noted that it has not yet exercised the option to withhold content from users in specific countries.

Once it does, it will alert its users to censored tweets by replacing the text of the post with a grayed-out tweet that reads, "This Tweet from @username has been withheld in: Country. Learn more." (See screenshot below.)

In its blog post announcing the changes, Twitter focused on its new ability to remove some tweets. Yet a Twitter Help Center post expanding on this tool noted that the site could also block access to entire accounts. "[I]f you see a grayed-out user in your timeline [...] or elsewhere on Twitter [...] access to that particular account has been withheld in your country," Twitter wrote. (See below.)

We've reached out to Twitter to clarify whether the company previously had the ability to block individual accounts in specific countries.

Twitter maintained that "one of our core values as a company is to defend and respect each user's voice," and the company noted that it has partnered with Chilling Effects, a non-profit focused on issues of free speech online, to create a site, http://chillingeffects.org/twitter, where it will alert its community when tweets have been blocked.

The company also said it will "attempt to notify" users whose content countries have requested withheld.

Alternately, users could just bypass the restrictions altogether: The Next Web has posted instructions for how to subvert the censorship.

Twitter users have been up in arms about the change, which many see as incompatible with Twitter's professed commitment to openness and a policy that has the potential to undermine Twitter's role in political movements, such as the pro-democracy protests that rocked Egypt last year.

"It's an affront on a free society & could be a PR disaster for Twitter after it's [sic] much praised role in the #Arabspring," tweeted @globalvybe.

Some users are attempting to organize a "#TwitterBlackout" on January 28 and intend to boycott Twitter in protest of the changes.

Others, most notably the director of international freedom of expression at the Electronic Frontier Foundation, have come to Twitter's defense.

"Let's be clear: This is censorship. There's no way around that. But alas, Twitter is not above the law," wrote the EFF's Jillian York. "I understand why people are angry, but this does not, in my view, represent a sea change in Twitter's policies. Twitter has previously taken down content-for DMCA requests, at least-and will no doubt continue to face requests in the future. I believe that the company is doing its best in a tough situation...and I'll be the first to raise hell if they screw up."

LOOK: How censored tweets and accounts will appear to users: