CAIRO, Egypt - An opposition activist spreads word of a forthcoming protest in the streets of Tehran. Another posts pictures of clashes between protesters and police.

As Iran's government cracks down on traditional media outlets in the aftermath of the disputed presidential election, tech-savvy Iranians have evaded censors and used the microblogging site Twitter to organize and spread information.

"When I'm not connected to Twitter, it means that I'm disconnected from the world because the state TV doesn't report many things!" wrote one user who identifies himself as "hamednz" who communicated with the Associated Press. His profile says he lives in Rasht, a city north of Tehran near the Caspian Sea.

Like all the Twitter users in Iran who agreed to be interviewed for this story, he did not want his identity revealed for fear of retribution from government authorities.

In Iran, Internet usage is mostly still a phenomenon of the affluent, young, and city-dwellers, and may overemphasize their numbers while ignoring more-conservative political sentiments among the nonconnected.

Still, the use of Twitter and other tools in Iran in recent days to send pictures and messages about the situation in real time to the outside world was a powerful example of how such tools can overcome government censorship efforts.

Twitter cofounder Biz Stone acknowledged the limited group of users in Iran, who don't necessarily represent the mainstream. "Because Twitter is still a nascent service the sentiment is likely narrow," Stone said by e-mail.

Supporters of reformist challenger Mir Hossein Mousavi are more likely to use Twitter and Facebook. Poorer, less-educated voters have flocked to President Mahmoud Ahmadinejad.

Iranians must outsmart government blocking to use Twitter, on which users post "tweets" limited to 140 characters. Twitter and other social-networking sites remained blocked in Iran yesterday. Users must go to other sites that post the tweets for them and let them read others' tweets.

Facebook was used to organize people before the election but was also blocked after the vote. Cell-phone service, which had been down in Tehran since Saturday, was restored Sunday, but Iranians still could not send text messages - another way to tweet - from their phones.