"Since the election, we have heard reports that users in Iran are having difficulties accessing Facebook," said Barry Schnitt, Facebook spokesman. "This is disappointing, especially at a time when Iranians are turning to the internet as a source of information about the recent election."

Judging by tweets since Friday's election, the censorship didn't slow some users down. Many then tweeted to share their tactics.

"Iranelection" was the top Twitter trend for the past few days, and a message thread led by "Persiankiwi" appeared to be orchestrating hacker attacks on official Iran websites while firing off updates on developments in the streets.

"We are going offline to get a phone free for calling out," Persiankiwi tweeted at midday. "We are also moving location - too long here - is dangerous."

A subsequent Persiankiwi tweet reads: "Attacked in streets by mob on motorbikes with batons - firing guns into air - street fires all over town - roads closed."

Do you think the people at Twitter ever thought they would be a life line for an actual revolution?