(Wired) -- Twitter confirmed Tuesday evening that its microblogging site has been shuttered by Egyptian authorities. This came hours after widespread reports that access had been cut off, as Egyptians took to the streets in what many hope and some fear would be a sequel to the revolution in Tunisia last week.
The day's speculation that the Mubarak administration might have pulled the plug on Twitter underscored the power of the site and other social networks as tools to both coordinate and disperse news of a citizen uprising. Twitter, Facebook and YouTube were widely used in Tunisia's recent uprising and in Iran last year.
But it remains an open and hotly debated question about how much of a role these tools actually play in real-world social movements, with some critics rightly pointing out that it becomes tempting for analysts to give more credit to the new and sexy tools than they actually deserve.
"We can confirm that Twitter was blocked in Egypt around 8 a.m. PT today. It is impacting both Twitter.com @applications," the company tweeted from the handle @twitterglobalpr.
Earlier in the day, Twitter seemed unsure. "We're not experts on how Twitter is being used in highly developing situations 1000s of miles from our comfortable HQ in SF," the company tweeted from the same handle. In a separate tweet, San Francisco-based Twitter added, "the experts are those using Twitter on the ground and those coordinating with them around the world."
One of the leading authorities on Middle East censorship, who is based in Cairo, said in a telephone interview that his Facebook account was accessible but not his Twitter account. His ISP, he said, is TE Data, that nation's largest internet service provider.
The source, who requested anonymity for fear of retribution, said some Egyptians using the Nour ISP were getting access to Twitter.
"Twitter, it's almost across-the-board inaccessible in Egypt," he said. "Given the size of the crowds we saw in the streets, I wouldn't be surprised the outage was from the government. There's been calls to censor the internet here for ages."
ABC News reported from Cairo that Twitter was down and that as many as three people were killed as tens of thousands of protesters hit the streets demanding President Hosni Mubarak's 30-year reign come to an end.
Vodafone, using the handle @VodafoneEgypt, had tweeted "no blocking from our side!" It speculated that the outage may have been from "overload."
Jillian York, who compiles a crowd-sourced ledger of unavailable websites across the globe for the Berkman Center for Internet and Society at Harvard University, said the center had received about a dozen reports of Twitter being inaccessible inside Egypt.
"We cannot confirm for sure if twitter.com is blocked," she said in a telephone interview early Tuesday.
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