Iran has one of the most vibrant blogging communities in the world - despite government boasts that it blocks five million websites. The BBC's Jon Leyne in Tehran is spending the day with bloggers to see what makes them tick.
Tehran blogger Jadi says his website is blocked inside Iran
With much of the official media controlled by the government or hardline conservatives, the internet has become the favoured way of communicating for Iran's well-educated and inquisitive younger generation.
Go online in Iran and you will find blogs or websites covering every topic under the sun.
Politics, of course, but also the arts, Hollywood cinema, women's issues, women's sport, pop music. Whisper it quietly, there is even an online dating scene in the Islamic Republic.
Day-by-day there is an intriguing cyber-war, as the government wrestles for control of the internet, and Iran's bloggers wrestle it back.
Iran hosts around 65,000 bloggers, and has around 22 million internet users. Not bad for a country in which some remote areas do not yet have mains electricity.
Even some journalists who work in the mainstream media use the internet to publish articles they can not get past their newspaper or programme editors, or the official censors.
The real attraction for bloggers, in this claustrophobic political climate, is that someone is listening.
That is the view of Seyed Vahid Aqili, assistant professor of mass communications as Islamic Azad University in Tehran.
"The young generation now have access to the world, to express their ideas and their beliefs and their attitudes. The internet is a good vehicle to let people express themselves," he says.
Life online in Iran is simply completely divorced from anything you see or hear in the official media
Even on the internet, though, free speech in Iran is limited.
Amir used to write a political blog. While he insists he did not include anything "offensive", one day he switched on his computer, to find his blog had been blocked by the authorities, just for daring to discuss politics.
To get around the restrictions, many websites are forced regularly to change their internet address.
Internet users in Iran learn to download anti-filtering software and other technology to beat the restrictions.
There are also some recent reports of bloggers having been arrested, though the facts are hard to pin down.
And a few months ago, parliament began considering a law that could impose the death penalty on bloggers found guilty of using the web to spread corruption, prostitution or apostasy.
It is not clear what progress the bill has made.
Yet, sometimes government attempts to control the internet are strangely half-hearted.
An ordinance recently urging bloggers to register with the Ministry of Culture and Islamic Guidance was quietly dropped after few people complied.
President Ahmadinejad has his own blog
Perhaps the authorities realise that screwing the lid down too tight could be counter-productive.
Nevertheless the authorities are clearly worried by the impact of the internet on the Islamic society and culture they work to foster.
In a recent publication, the Revolutionary Guards complained of "internet imperialism" and warned that the CIA was trying to use the internet to provoke a "velvet revolution" in Iran.
They accused international media, including the BBC, CNN and The New York Times, as being part of this conspiracy.
Yet the striking thing about the internet in Iran is how un-political it is.
Life online in Iran is simply completely divorced from anything you see or hear in the official media.
"The majority of blogs focus on social matters, art topics, personal diaries, poems, and commentary on topics ranging from arts to cinema and music," said Dr Aqili.
"Most bloggers just want to express their ideas and their private lives to their friends," said Amir.
"It's something the youth in Iran need, because they do not have any special entertainment or hobby. And they cannot say anything freely."
But even if there is no direct political threat to the government, what takes place on the Iranian internet does provide a fascinating commentary on Iranian society.
It is not a picture the defenders of the revolution may be so happy about.
Take pop and rock music. Playing the electric guitar in public is banned (the devil's instrument!). Singing in English is a definite No. As for women singing solo - forget about it.
So all of this has gone underground, online.
Iran's Revolutionary Guards are to get their own blogs
The hundreds or possibly thousands of Iranian bands distribute their music on the internet, with everything from heavy metal to trance music. And everyday you can hear the music played on tape machines in taxis across Tehran.
Not that Iran's rock music generation have a monopoly on the internet.
The government recently announced plans to launch 10,000 weblogs for 10,000 bases of the Basij - the militia arm of the Revolutionary Guards.
Already the religious capital of Qom is one of the best connected cities in Iran. Clerics research Islam, and publish their findings on numerous religious websites.
The government also promotes its ideas on the web. News about President Mahmoud Ahmadinejad often emerges first on his own personal website.
Iran has often lived under a siege mentality since the Islamic Revolution three decades ago.
Satellite TV dishes are banned. International credit cards are useless in the country. Political, religious and military leaders caution the dangers from abroad, and warn of the danger of attack.
Yet at the same time Iranians are fascinated by the rest of the world, and cherish their contact with foreigners. Never more so than in Iran's flourishing internet culture.
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