It was called the "Twitter Revolution" - the mass street protests following Iran's questionable June elections that were beamed to the world via social media and other online tools despite the government's media blackout.
This week, a loose, multi-national network of protesters, bloggers, Web developers and everyday Internet users has ramped up again in the wake of renewed anti-government street demonstrations that turned deadly Sunday on Ashura, a Shiite Muslim holy day commemorating the death of 7th Century cleric Imam Hussein.
This time, Internet analysists and online activists involved in the movement have told CNN that a government initially caught flat-footed at how easily information flowed out of the country was ready to fight back.
"It's clear the government has been definitely restricting the Internet in a much more controlled way," said Cyrus Farivar, an Iranian-American freelance journalist who writes about technology issues. "They're definitely paying attention and, at the very least, trying to intimidate people."
And retaliation has been brutal - both for those taking to the streets and those spreading the word online.
One of the most compelling videos to emerge from the recent unrest showed what the people who posted it said was an Iranian government vehicle plowing into a crowd of protesters, apparently running over and, they say, killing a woman.
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