More than three weeks after Iran's disputed presidential election, at least 33 journalists are behind bars this weekend. Iran now has more journalists in prison than any country in the world, says the charity Reporters Sans Frontiers. Dozens of foreign journalists were booted out of the country or arrested following the election, and the entire editorial staff of one Iranian newspaper was incarcerated.

But if the Iranian government had hoped to block the spread of information, it was hopelessly thwarted by Twitter and mobile phone cameras in the hands of ordinary Iranians, who transmitted nuggets of information and images to the internet as the violence began. By clamping down on recognised journalists, Iran unwittingly unleashed a multi-headed hydra of citizen journalists chronicling events at the frontline.

So it was timely of Google to launch a site last week promoting amateur journalism. YouTube Reporters aims to "help citizens learn more about how to report the news, straight from the experts". Videos have been posted by professionals such as Bob Woodward, the Washington Post reporter who co-broke the Watergate scandal and Nick Kristof of The New York Times.

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Newspapers have long been accused of hastening their own demise by giving content away free online, so it's perhaps even odder for professional journalists to be queuing up to give away their trade tips. But this is a pivotal moment in the democratisation of the media. The Daily Mail and General Trust launched its Local People network last week, unveiling the first of 50 community websites. The aim is to build a network of sites in which readers contribute content by uploading stories and images. It is yet another example of the growth of collaborative journalism already exploited by US sites such as The Huffington Post and The Daily Beast.

What emerges from many of the tutorials posted on YouTube Reporters so far is, ironically, the case against it. Stories need verification, say the old hands. The first principle of journalism may be to gather information but, as Bob Woodward stresses, more important still is the checking for accuracy. While the Tehran riots highlighted the value of eyewitness accounts, credibility remains a problem. One tweet reported a massacre that never happened. Yet with few journalists on the ground, news agencies were forced to compose a picture of unfolding events from the evidence available. Even the US government became dependent on the stream of live tweets, asking Twitter to postpone maintenance work on their server until the riots were over.

It was, says Arianna Huffington, founder of the Huff Po, a "defining moment for new media". Huffington is among those who have contributed to YouTube Reporters. Her site, which boasts 13,000 citizen journalists, ran a live blog during the riots, reporting events within minutes of them happening. This has prompted fears the site is lending credibility to potentially false information, although Huffington denies this, pointing out that she employs a news editor who "curates" reports as they come in, "adding value" by filtering and weaving them with wire copy. "It was the only way to circumvent what the Iranian regime was trying to do, which was to control all information," she says.

Huffington says the challenge ahead is not how to save newspapers but how to preserve journalism. To that end, she has established, with other donors, a £1.2m fund for investigative reporting which will fund 10 staff reporters. Saving journalism is also what prompted Tina Brown, the former editor of Vanity Fair, to launch the Daily Beast. She says the tipping point for internet journalism has been reached, and believes advertising will begin to follow. "The internet was founded by geeks so visually it wasn't a good place to advertise," she told the BBC, "But as websites become more attractive they become more attractive to advertisers. Big ticket advertisers have yet to come aboard. We're breaking through in that area by creating a brand that is so attractive that advertisers want to be a part of it."

While newspapers wait to see whether Brown is proven right, many are concentrating on clawing back free content from the net, with at least three national newspapers looking into re-erecting pay barriers. The way in which the story of Michael Jackson's death was broken, via free-to-view gossip website TMZ, is a timely reminder of the threat to traditional media. Meanwhile in Iran, as the 33 journalists ponder their fates, the threat to journalism must seem rather more immediate.