Update 2:35 p.m. PT:

Twitter has responded to the outcry surrounding its new policy of withholding content [5], posting on its blog that the policy will actually promote free speech rather than inhibit it.

Twitter will not filter posts before or as they go up. Instead, it will be reactive, taking down posts that a certain country objects to. In doing so, it will be able to keep that content available to users in the rest of the world.

"Besides allowing us to keep Tweets available in more places, it also allows users to see whether we are living up to our freedom of expression ideal,“ the post said. The company also said there is no "magic" to the timing. They have been working on a more transparent withholding policy.

Several media folks and tech observers have also defended Twitter [6], arguing that the blame lies with the specific repressive countries, not the social media giant.

They have compared Twitter and Google’s transparency on withheld content favorably to that of Facebook.

"Wish Twitter phrased their announcement, 'When governments force us to censor, here's how we'll tell you. Facebook, will you do this too?" Anil Dash tweeted. [7]

Earlier:

It was only two weeks ago that Twitter was protesting online censorship in the form of anti-piracy bills SOPA and PIPA. Now now the social networking site faces a surge of opposition to its own censorship practices.

Twitter announced in a blog post [5] Thursday that it will now block specific tweets on a country-by-country basis should the messages violate the laws of those countries.

One of the worries is that Twitter has been a powerful tool in the protest movements that have surfaced across the globe in the past year, whether in the Arab Spring or the anti-austerity protests in Europe.

The fear is that the new policy will limit its utility in such instances.

Users have responded by promising to boycott the site on Saturday, and the media has blasted the company for what it views as blatant censorship.

Forbes’ writer Mark Gibbs dubbed the move “social suicide”  [8]and many others have chimed in to voice their objection.

The boycott of Twitter is being promulgated by the hashtag #TwitterBlackout [9] -- not all that different from the #SOPABlackout tweets from earlier this month. In another case of overlap with the SOPA/PIPA fight, hacking network Anonymous seems to oppose the move.  [10]Not know yet is whether it will act.

It's doubtful that enough people will stop using the service to have an impact, nor would a brief Twitter shutdown damage its business. However, the threats are clearly more about sending a message than crippling the now ubiquitous messaging platform.

Also read: SOPA Generates 2.4M Tweets; Who Says It Limits Online Expression?  [11]

The site's reasoning for the change was stated in its blog post: "As we continue to grow internationally, we will enter countries that have different ideas about the contours of freedom of expression. Some differ so much from our ideas that we will not be able to exist there." 

Observers see this as Twitter caving to the power of oppressive and restrictive foreign governments. They don't want to anger those countries too much, lest they block Twitter.

To some, this is appalling [12]. To others, it’s just business. [13]

Either way, Twitter finds itself on the other end of the censorship fight for one of the first times.

Welcome to adulthood, Tweeps.