Northern Virginia is a relatively quiet place. Seismically speaking.

So when the ground started rumbling violently on Tuesday afternoon, the locals had an idea something was wrong. But what? For the first few minutes, there was no official news except for a series of “Tweets” — mini alerts broadcast by wired locals tapping what they saw, felt and heard into their mobile phones and on to their Twitter web pages. Twitter, a popular micro-blogging site that counts more than a million users, became the only news source on a fast-breaking story in those tense first minutes. About 90 minutes later, a local radio station was able to report what Twitter users had been Tweeting all along — it was a rare earthquake, measuring 1.8 on the Richter scale, that had hit the East Coast. This was not a first. Twitter users used the technology to offer on-the-ground reportage of the San Diego wildfires last autumn and specific detail from the US presidential election trail.

Twitter — and its rivals Pownce, Jaiku and Dodgeball — is the kind of mobile social networking application that is shrinking the world to the size of a small screen. The idea that we can receive and provide instant updates about what’s happening in any part of the planet at any given time, far from the news vans and big city reporters, is at the heart of the mobile networking movement. With a mobile phone or net-connected computer (and these days, they are one and the same), plus two eyes, two ears and a little bit of curiosity, ordinary civilians have the capability to report on their world to the world.

And there’s vast potential. Analysts at Informa, a technology consultancy, report that there are now more than three billion mobile handsets in use in the world — one for every two people on the planet. Thus, mobile networking applications such as Twitter and aka-aki that are capable of connecting these three billion people to one another become a powerful force for political and cultural change.

With billions of eyes watching, the technology, it is hoped, can introduce a fresh level of accountability to repressive regimes and opaque business operations. It also has been a boon for the celeb gossip pages, turning fans with mobiles into a new generation of paparazzi.

To be sure, aided by mobile networking technologies, the citizen journalism movement has given rise to a powerful form of grassroots news gathering. The mobile-crazed South Koreans formed Ohmynews in 2000 to report on every aspect of society, a model that is being replicated in press-antagonistic parts of Africa and the Middle East. So, impressed with the mobile-networking phenomenon, Reuters is working on incorporating a Twitter-style news-reporting function for its correspondents to join this rapid-fire approach to journalism.

And the legion of citizen journalists is on the brink of becoming an even greater force. The rapid deployment of mobile handsets equipped with high-speed data transfer technology — HSPA for short — means consumers will have broadband-ready mobiles capable of sending and receiving videos, pictures and recordings to and from the web in a flash. By the end of the year, 40 million people will own these powerful handsets, Ovum, the tech consultancy, predicts.

As the power of the technology grows, introducing greater bandwidth and storage capacity into ever-smaller devices, the social networking phenomenon will expand too, analysts say. At the moment, it’s the domain of geeks and gadgetheads. As the people in northern Virginia learnt this week, it’s not all idle geek chat.

Bernhard Warner writes about technology for Times Online

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